Adds composite actions to generate and check locks

[komish]

These actions will read the given state of the repository and determine what chart names are associated with what filesystem paths. they're designed to prevent charts being stored with the same name.

These actions currently have no callers, but a non-break worfklow dispatch can be added to test their functionality before they're integrated into CI-breaking workflows.

An example of how check-chart-locks would be called:

      - name: Check if chart name is locked
        id: determine-lock-status
        uses: ./.github/actions/check-chart-locks
        with:
          chart-name: ${{ steps.gather-metadata.outputs.chart-name }}
          fail-workflow-if-locked: 'false'

An example of how generate-chart-locks would be called:

  - name: Generate Locks
    id: generate-locks
    uses: ./.github/actions/generate-chart-locks