Separate Patternkit Caches From Discovery Cache

Problem/Motivation

The cache bins for discovered pattern libraries and pattern definitions are currently being loaded into the discovery cache bin, but by default this bin is backed using the chained fast backend. Since this cache data doesn't change frequently and is typically only loaded and written once per request, this may work better going into the database cache by default where it can more easily be shared between web heads as well. If this gets separated to an independent new bin this can be backed by the database by default while still allowing individual sites to customize the data handling as desired.

Steps to reproduce

1. Clear all caches
2. View the cache_discovery database table
3. Observe the presence of the following cid entries:
   • patternkit.library_namespaces
   • patternkit_pattern_defintiions:*

After this change, these cache entries should be stored in the cache_patternkit table instead.

Proposed resolution

Create a new patternkit cache bin
Inject the new bin into related services
Store library namespaces and pattern definitions in new cache bin

Remaining tasks

User interface changes

None

API changes

None

Data model changes

New cache_patternkit database table