Fill out more of the C++ API for components (#11889)

* capi: Add a C++ API for `component::Linker`

Just a bare-bones API for now with functionality that's possible to fill
out. Notably instantiatio

Fill out more of the C++ API for components (#11889)

* capi: Add a C++ API for `component::Linker`

Just a bare-bones API for now with functionality that's possible to fill
out. Notably instantiation and defining functions is not yet possible in
C++. Some more feature-parity is also added with the core linkers as
well.

* capi: Add bindings for component instances

* capi: Delete wasip2.h header file

Upon reflection I realize that this is not actually necessary and is
otherwise a duplicate of the functionality in `wasi.h`. All of the
functionality in `wasi.h` is already supported to power WASIp2-defined
APIs in a linker, which is enabled by the `WasiView` trait redirecting
to the `WasiView for WasiP1Ctx` implementation. This is similar to how
the `wasmtime` CLI works where a P1 context is always created and then
it's conditionally used for either core wasm or components.

Effectively this is a deletion of duplicate functionality in the C API
but no underlying functionality is lost. Translating information to
preexisting WASI calls will work the same as using the wasip2 APIs before.

* capi: Start bindings for component functions

* capi: Bind component values in the C++ API

* capi: Finish bindings for component functions/linkers

All the pieces are now in place to use the C++ API in testing.

* Fix compilation of CLI

* Fix compile on MSVC

* Try again to fix msvc compat

* Fix `get_f32` and `get_f64` return values

* Fix signed return values

* Remove no-longer-needed `capi_transfer` function

* Try to fix msvc again

* Remove std::optional constructor of `Val`

* Fix another namespace clash on msvc

* One day I surely may understand a fraction of either C++ or MSVC, but
today is not that day.

* Document internal macro

* Add other internal docs

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