RFE: migrate ~/.rpmmacros and ~/.rpmrc to ~/.config/rpm/

[pmatilai]

Commit f24ca5e added support for rpm configuration in XDG ~/.config/rpm but left existing setups alone. Going forward we'll want to be able to rely on having a whole directory available for our purposes, so we should start migrating old setups to the new world order. Something like:

• detect a legacy setup (non-symlink ~/.rpmmacros and/or ~/.rpmrc)
• create ~/.config/rpm
• move legacy paths there
• for each legacy path moved, plant a symlink to the original location

Would be nice to do this automatically (accompanied with a warning message) but at the very least we should provide and suggest a script to run to let users easily migrate.