#### Description
To facilitate the work in
https://github.com/open-telemetry/opentelemetry-collector/pull/11204 as
some breaking changes and some deprecations, this PR adds the new
pipeline module separately so that future PRs can handle the breaking
changes and deprecations.
In order to make `Signal` uninstantiable outside of this repo, while
still being extendable in places like `componentprofiles`, a new
internal module is added to handle the `Signal` logic. To reduce the
dependency sprawl that would happen if `signal` was an internal package
in `go.opentelemetry.io/collector`, I made it a module, similar to
`globalgates`.
<!-- Issue number if applicable -->
#### Link to tracking issue
Related to
https://github.com/open-telemetry/opentelemetry-collector/pull/10947
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#### Testing
Added unit tests
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#### Documentation
Added godoc comments
Bogdan Drutu
Philip Dubé
Tyler Helmuth