ci: fix schema and markdown generation workflows

[lfleischmann]

Description

1. Schema generation workflows do not have correct permissions/cannot bypass branch protection rules.
2. Schema and markdown generation workflows can end in a "race condition" where one workflow pushes to the repository and the other workflow then has a stale main head ref when attempting to push. This fails the workflow.

Implementation

1. Schema generation workflows no longer attempt to push directly to the main branch but open pull requests using the gh pr create command from the GItHub CLI (is already installed in the Actions runner image).
2. Because schema generation workflows no longer automatically push to the main branch there are no more race conditions. As for the markdown workflows: a "delay check" was added to the import workflow that uses the gh api command of the GitHub CLI to request running config workflow runs from a GitHub REST API endpoint. If an in_progress run of the config workflow is found, the import workflow will delay its push to the wiki repo by sleeping for some time.