Continuation of package standardization

This is a continuation of the packaging standardization efforts discussed in kea#2220 (closed) and implemented in !34 (merged).

Goals:

• Rename alpine premium hooks to be consistent with rpm and deb packages
• Make kea run under kea user on rpm systems
• Move debian python3-isc-kea-connector package contents into isc-kea-admin package
• Add service aliases on debian to the shorter names used on rpm and alpine systems
• Fix up lockfile locations. Addresses kea#2398 (closed) in our own packages.