add slash commands

[humanendpoint]

for starting workflows, adding a repo? add a user to repo

[humanendpoint]

• starting GitHub workflow
• create a new file and create a new pull request.
  • this means base64 encoding the file contents then using https://docs.github.com/en/rest/repos/contents?apiVersion=2022-11-28#create-or-update-file-contents
  • probably at this point ensure the pull request can be created
  • use /gh file $ENCODING BRANCH
  • then /gh create BRANCH
  • ephemeral message with any error