docs: document merge reqiurements

[pichlermarc]

Which problem is this PR solving?

• until now, we did implicitly apply the same merge requirements from https://github.com/open-telemetry/opentelemetry-js in this repository. However, some concepts are not considered in the original merge requirements: component lifecycle and component ownership.

Short description of the changes

• adds the pull request merge requirements from https://github.com/open-telemetry/opentelemetry-js to this repository's CONTRIBUTING.md
• amends the merge requirements to consider component ownership
• clarifies that merge requirements apply to all components, regardless of of their current stage in the component lifecycle

fyi @open-telemetry/javascript-maintainers

[codecov]

Codecov Report

Merging #1553 (033868f) into main (784a422) will not change coverage.
The diff coverage is n/a.

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #1553   +/-   ##
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  Coverage   96.06%   96.06%           
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  Files          14       14           
  Lines         914      914           
  Branches      199      199           
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  Hits          878      878           
  Misses         36       36