Proposal: Make internal/sharedcomponent as a non-internal module

[VihasMakwana]

We have two separate implementations of an internal/sharedcomponent module: one for the core and one for contrib. Both of the implementations have different APIs and different methods but they fundamentally do the same thing i.e use a map to track unique component per config.

I propose we move the contrib implementation to the core and expose it as a public API.

There couple of good arguments to make this a single, public API:

• We no longer need to maintain two separate internal versions of the same functionality.
• This allows other open-source collector distributions to take advantage of sharedcomonent.
• simplified dependency. Now that go.opentelemetry.io/collector/internal/sharedcomponent is a separate module, it becomes easy for us to make it public and update contrib to use it.

@open-telemetry/collector-maintainers @open-telemetry/collector-contrib-maintainers let me know your thoughts on this!

[VihasMakwana]

Related: #4266

[TylerHelmuth]

We should not make this helper public until #10534 is sorted.