This commit implements an experimental integration with tsc_wrapped, where
it can load the Angular compiler as a plugin and perform Angular
transpilation at a user's request.
This is an alternative to the current ngc_wrapped mechanism, which is a fork
of tsc_wrapped from several years ago. tsc_wrapped has improved
significantly since then, and this feature will allow Angular to benefit
from those improvements.
Currently the plugin API between tsc_wrapped and the Angular compiler is a
work in progress, so NgTscPlugin does not yet implement any interfaces from
@bazel/typescript (the home of tsc_wrapped). Instead, an interface is
defined locally to guide this standardization.
PR Close#34792