Complete migration to GitHub

[jonahgraham]

The Eclipse Packaging Project is now in GitHub (this repo!). This issue is to track the items left to do to complete the migration with a general goal of getting this all done by 2023-06 M1 on 13 April.

• Update main CI job with new URL
• Update remaining CI jobs with new URL
• Add PR validation build (replacement for https://ci.eclipse.org/packaging/job/epp-tycho-build.gerrit/)
• Move releasing steps from hackmd to GitHub issues (with endgame tag)
• Consider closing out old bugs in EPP (with Resolved -> Moved)
• Find and update all locations that say file bugs in bugzilla and migrate that to GitHub issues #14
• Create a template for issues
• Add branding #15

[jonahgraham]

Raised https://gitlab.eclipse.org/eclipsefdn/helpdesk/-/issues/2951 to get GitHub actions + bot for JIPP.

[jonahgraham]

Migrated tracking from https://hackmd.io/@jonahgraham/eclipse-epp-release-process to github issues in #6, see #5 for the first example or endgame Release process steps for all of them. There will surely be some refinements done as we progress, but this seems to be a good starting point.