* ci: first attempt at adding a gated docker PR Publish (#1038)
* ci: first attempt at adding a gated docker PR Publish
* See if we can use contexts to inject variables after approval
* fix build command
* try alternative context
* docs: pull request template that spells out PR checklist
* change context back to Docker Hub
* Switch optional approval to another workflow
* Make docker builds faster
* Update .github/PULL_REQUEST_TEMPLATE/pull_request_template.md
