Automate per-package release for specific components

[lmolkova]

Description

Adds automation allowing to release individual components.
Packages that can be released individually are:

• excluded from the main release
• must have individual changelog
• follow the same release process and versioning rules:
  • prepare minor/patch that creates
    • long-term package-release/{package}/v{version} branch
    • PRs to update changelog and versions in release branch and main
  • release
• adds changelogs and versions for for components that are currently released manually as individual packages (opentelemetry-resource-detector-azure, opentelemetry-sdk-extension-aws, opentelemetry-propagator-aws-xray)

Related to #2858

Type of change

How Has This Been Tested?

Tested in the fork https://github.com/lmolkova/opentelemetry-python-contrib/actions

• Preparing + releasing new minor or patch version of an unstable package
• Preparing + releasing 'common'

Does This PR Require a Core Repo Change?

• No.

Checklist:

See contributing.md for styleguide, changelog guidelines, and more.

• Followed the style guidelines of this project
• Changelogs have been updated

[lzchen]

LGTM! Thanks for working on this! Just a few minor comments. Feel free to reach out to one of the maintainers to actually test this out with an actual package once it is merged.

[lmolkova]

@open-telemetry/opentelemetry-python-contrib-approvers could I get some eyes on it please? Thank you!

[aabmass]

Thanks for working on it @lmolkova

It seems reasonable to me and I think @lzchen has the most context and has already approved. I'm OK to go ahead with this.