R1:7d4b323da2bd

Store Almanac "service types" instead of "service classes"

Summary:
Ref T10449. Currently, we store classes (like "AlmanacClusterRepositoryServiceType") in the database.

Instead, store types (like "cluster.repository").

This is a small change, but types are a little more flexible (they let us freely reanme classes), a little cleaner (fewer magic strings in the codebase), and a little better for API usage (they're more human readable).

Make this minor usability change now, before we unprototype.

Also…