[confmap]- Implement yaml tags based strategy for merge append mode

[VihasMakwana]

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Description

This PR implements the merging of lists by utilizing the yaml tags. This is the implementation of RFC: https://github.com/open-telemetry/opentelemetry-collector/pull/13256

We following these steps to merge two configurations:

1. We go through the yaml tree of the config and search for tags.
2. We keep track of current path in the hierarchy and record the path in a "map", if user has specified a merging tag.
3. Once the yaml tree is traversed, we go through recorded paths and merge the lists for those paths.

Relates https://github.com/open-telemetry/opentelemetry-collector/pull/13256 Relates https://github.com/open-telemetry/opentelemetry-collector/issues/8754