Add fulltext search support

Originates from https://github.com/FAForever/downlords-faf-client/issues/1681

In general Elide supports fulltext search utilising Hibernate Search with a [SearchStore](https://github.com/yahoo/elide/tree/master/elide-datastore/elide-datastore-search).
This would require to setup either Solr or Elastic and annotate the required entities.

- [ ] Evaluate usage of Solr vs Elastic
- [ ] Investigate configuration of Hibernate search
- [ ] Add Solr or Elastic to faf-stack
- [ ] Add Elide SearchStore
- [ ] Add Hibernate Search configuration to application.yml
- [ ] Add Hibernate Search configuration to faf-stack
- [ ] Annotate relevant entities
- [ ] Ensure initial creation of indices