Move elasticsearch related specs into search proxy specs
Summary
Many of the testing logic resides under ee/spec/models/concerns/elastic. We can consider moving some under ee/spec/lib/elastic/latest, where proxy objects resides in, after admin UI has been merged (to reduce possibility of conflict resolving).
Improvements
Many logics are now moved to the sub classes of ApplicationClassProxy and ApplicationInstanceProxy. Moving the specs can make this easier to find corresponding specs.
Risks
Since only the specs are involved there is no risk.
Involved components
ee/spec/models/concerns/elasticee/spec/lib/elastic/latest