Implement indexed entities cache

[arkid15r]

As Algolia has a cap of 10K free search requests per month it would make sense to avoid querying index backend for the same search queries more than once.

The implementation should utilize Django cache https://docs.djangoproject.com/en/5.1/topics/cache/

The caching system should work for all entities (we currently have projects and issues).

The default TTL should be 86400 as we update the index on a daily basis. The update process must invalidate all cached entities.

[onass1]

/assign