Make extension review process compatible with GitLab

Created by: seancolsen

1. The extension review process described here...

   • https://docs.civicrm.org/dev/en/latest/extensions/publish/#automated-distribution
   • https://docs.civicrm.org/dev/en/latest/extensions/lifecycle/#formal-review

   ...is dependent on Jira.

2. Jira reads:

   Issue creation was disabled on March 31st 2018.

These points seem incompatible to me.

Can we offer an extension review process that doesn't depend on Jira?

@ginkgofjg @twomice any thoughts?