Move tools.cdt to GitHub

Summary

Hello Webmasters, The Eclipse CDT project (tools.cdt) is ready to migrate to GitHub at a time that is mutually convenient to you and the project.

The project is tracking all the parts we need to do in our tracker - https://github.com/eclipse-cdt/cdt-infra/issues/62 I have extracted the items from that issue which I believe need EF webmaster to do. Of course as you have done this a few times already you may have other lists already, so please let me know.

• Create https://github.com/eclipse-cdt/.github
  • Do not enable Issues, Discussions, Wiki - these will all be handled by the main repo https://github.com/eclipse-cdt/cdt
• Archive https://github.com/eclipse-cdt/cdt-new-managedbuild-prototype
• Archive https://github.com/eclipse-cdt/cdt-vscode
• Migrate CDT's git repo stored in gerrit to https://github.com/eclipse-cdt/cdt
  • This may be as simple as stopping mirroring https://git.eclipse.org/r/admin/repos/cdt/org.eclipse.cdt,general?
• Rename master branch to main
• Delete/disable https://github.com/eclipse-cdt/cdt wiki
• Enable Issues and Discussions on https://github.com/eclipse-cdt/cdt
• Set description on https://github.com/eclipse-cdt/cdt to Eclipse CDT™ C/C++ Development Tools
• Make https://git.eclipse.org/r/admin/repos/cdt/org.eclipse.cdt,general readonly
  • There is a lot of stuff on CDT's gerrit that is of differing value. My preferred option to leave CDT's gerrit in read-only state until gerrit is shutdown. That should give plenty of time for people to extract anything of value from gerrit and contribute it to CDT (as a GitHub PR)
• Protect branches from force pushes, deletions and direct pushes
  • All pushes need to be via PR.
• Delete/disable https://github.com/eclipse-cdt/cdt-infra wiki

There are other things to do in the next phase once we get everything working on GitHub (like disabling bugzilla, forums, etc)