Fix externref/anyref ownership in C/C++ API (#11799)

* Fix externref/anyref ownership in C/C++ API

This commit is a follow-up to #11514 which was discovered through
failing tests in the wasmtime-py

Fix externref/anyref ownership in C/C++ API (#11799)

* Fix externref/anyref ownership in C/C++ API

This commit is a follow-up to #11514 which was discovered through
failing tests in the wasmtime-py repository when updating to Wasmtime
37.0.0. Effectively a combination of bugs in the Rust API meant that it
wasn't possible to use `externref` or `anyref` bindings correctly. The
Rust changes in this commit are:

* `wasmtime_val_unroot` correctly drops the value now as opposed to
effectively being a noop from before (typo of using `as_externref` vs
`from_externref`).
* `wasmtime_{anyref,externref,val}_t` now have a `Drop` implementation
in Rust to correctly drop them if a value in Rust is dropped. This is
required to correctly manage memory in the `wasmtime_func_{call,new}`
implementations, for example.
* `wasmtime_{anyref,externref,val}_clone` no longer have an unnecessary
context parameter.
* `wasmtime_{anyref,externref,val}_unroot` no longer have an unnecessary
context parameter.

Changes in the C/C++ APIs are:

* `Result::{ok,err}_ref` APIs were added in addition to the preexisting
rvalue accessors.
* Loading/storing typed arguments now has an overload for `const T&` and
`T&&` which behaves differently. Notably transferring ownership for
`T&&` and not for `const T&`. This means that passing parameters when
calling a wasm function uses `const T&`, but passing results from a
host import uses `T&&`.
* `TypedFunc::call` now uses `const Params&` instead of `Params` to
explicitly specify it doesn't modify the parameters and forces using
the `const T&` store method.
* `Store::gc` is now a convenience method for `store.context().gc()`
* `ExternRef`, `AnyRef`, and `Val` now have ownership semantics and
destructors. This matches the spirit of #11514 for Rust but models it
in C++ as well. This required filling out move/copy
constructors/assignments.
* The explicit `ExternRef` now takes `std::any` instead of `T`.
* Minor issues related to ownership are fixed in `Val` bindings.

Valgrind was used to ensure that there were no leaks for the test suite
which additionally resulted in a number of `*_delete` calls being added
to tests using the C API (accidental omissions).

The original goal of this change was to be a patch release for 37.0.1 to
enable updating wasmtime-py to the 37.0.x releases of Wasmtime. In the
end though the changes here were broad enough that I no longer feel that
this is a good idea, so wasmtime-py will be skipping the 37 version of
Wasmtime.

* Run `clang-format`

prtest:full

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Split final C++ items out of `wasmtime.hh` (#10692)

* Split final C++ items out of `wasmtime.hh`

Now `wasmtime.hh` is just an "amalgamation" header to include
everything, yay!

* Format files

* Tr

Split final C++ items out of `wasmtime.hh` (#10692)

* Split final C++ items out of `wasmtime.hh`

Now `wasmtime.hh` is just an "amalgamation" header to include
everything, yay!

* Format files

* Try to fix MSVC

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Run `clang-format` over more files (#10689)

We were already running it over most `*.c` files and other ones but
forgot the `*.hh` and `*.cc` extensions which are being used for C++
bindings, so add

Run `clang-format` over more files (#10689)

We were already running it over most `*.c` files and other ones but
forgot the `*.hh` and `*.cc` extensions which are being used for C++
bindings, so add those in and then run the formatter.

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Split C++ Func/Table/Memory/Global to their own headers (#10688)

I did my best to separate out headers but I don't understand enough C++
to fully sever `val.hh` and `func.hh` so they sort of circula

Split C++ Func/Table/Memory/Global to their own headers (#10688)

I did my best to separate out headers but I don't understand enough C++
to fully sever `val.hh` and `func.hh` so they sort of circularly
reference each other now.

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Split out some more C++ types to their own headers (#10658)

* Move C++ WASI configuration to its own header

* Move C++ `Store` to its own file

I tried binding `wasmtime_store_epoch_deadline_callba

Split out some more C++ types to their own headers (#10658)

* Move C++ WASI configuration to its own header

* Move C++ `Store` to its own file

I tried binding `wasmtime_store_epoch_deadline_callback` in C++ but I
don't know enough C++ to figure out the syntax for doing so.

* Move C++ Val to its own header

Also bind `AnyRef` while I'm here with some small tests.

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Move the C++ `Trap` and related types to its own header (#10647)

Move C++ `Config` to its own header (#10634)

Also bind APIs which were added since this was created. Also copy over
some `#define` guards for the C methods into the C++ header as well. And
finally u

Move C++ `Config` to its own header (#10634)

Also bind APIs which were added since this was created. Also copy over
some `#define` guards for the C methods into the C++ header as well. And
finally update tests for what's added.

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c-api: Bring wasmtime-cpp into this repository (#10582)

* c-api: Bring wasmtime-cpp into this repository.

`wasmtime-cpp/include/wasmtime.hh` -> `/crates/c-api/include/`
`wasmtime-cpp/tests/*` -> `/

c-api: Bring wasmtime-cpp into this repository (#10582)

* c-api: Bring wasmtime-cpp into this repository.

`wasmtime-cpp/include/wasmtime.hh` -> `/crates/c-api/include/`
`wasmtime-cpp/tests/*` -> `/crates/c-api/tests/`
`wasmtime-cpp/examples/*` -> `/examples/`

See discussion in #10566 for more context.

* Make tests disabled by default prtest:full

* Mention C++ API in the c-api README

* Enable C++ only for tests

* Add *.hh files to doxygen

This requires disabling warnings on undocumented, as `wasm.hh` has
undocumeted structures

Also fix urls in `wasmtime.hh`

* Re-enable `WARN_IF_UNDOCUMENTED`

This required excluding `wasm.hh`, `wasmtime::detail` namespace, and some
macros.

Also documented two overloads to `Func::call()`

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