[3.0] misc. fixes for the pending 3.0.22-rc1 release

Contains the following fixes:

• add "-rc1" in the NEWS to fix make dist failure
• add a release-debian target similar to the release-winxxx targets to generate the tarball for the release
• backport of !7703
• backport of !7704 (merged)
• backport of !7699
• misc. backport to build extras/tools cleaner and faster