Lots of configuration migration script fixes. New dirs in /etc.
Fix dir cleanup (broke the debian/rules ‘clean’ target).

This fixes commit fc3af440da27e3aa185b7c30863165208a0189ac.
Update unvanquished-server news file.
Merge branch 'master' into debian
Merge branch 'master' into debian; update changelog
Modify basepak.sh to handle pk3 names and versioning; fix empty-string tests.
Clang-specific warning is already covered by -Wpedantic
Don't allow clients to connect to a server that uses pk3dirs
Fix umask used when creating the pubkey.
Send loaded pk3dirs to the client and make the latter refuse to connect unless client.allowRemotePakDir has been enabled.
Update version number to 0.24.1
Merge branch 'debian'
Update Debian changelog.
Update .gitignore.
Merge tag 'v0.24.1' into gameplay/testing

Alpha 24, Point release 1