Add content-source matching functionality to the assembler

[Mpdreamz]

Introduce logic to match branches or tags against configured content sources. Extend CLI with 'content-source' commands and integrate GitHub action for content-source validation. Update project solution and configuration accordingly.

The idea being we can follow up and add

  metadata:
    if: github.event.repository.fork == false && contains(fromJSON('["push"]'), github.event_name)
    concurrency:
      group: ${{ github.workflow }}-${{ github.ref }}
    runs-on: ubuntu-latest
    steps:

      - name: 'Match'
        uses: elastic/docs-builder/actions/assembler-match@main
        with:
          repository: ${{ github.repository }}
          # only works for push
          ref: ${{ github.ref_name }}

As an additional step to the preview workflow while widening up our push triggers.

Example:

env GITHUB_ACTIONS=true dotnet run --project src/tooling/docs-assembler/ -- content-source match docs-content main

info ::e.d.t.f.topwatchFilter:: content-source match :: Starting...
info ::d.a.c.ntSourceCommands:: 'docs-content' 'main' is configured as 'current' content-source

::set-output name=content-source-match::true

::set-output name=content-source-name::current


        0 Errors / 0 Warnings / 0 Hints

info ::e.d.t.f.topwatchFilter:: content-source match :: Finished in '00:00:00.0906530'