Unmaintained Hibernate Search config for some entities

We currently have the Hibernate Search annotation @Indexed on these classes:

HAccount - queried by nothing that I can find - commented out in AccountDAO (update: removed by https://github.com/zanata/zanata-platform/pull/504)
HGlossaryEntry - queried by nothing that I can find (update: removed by https://github.com/zanata/zanata-platform/pull/576)
HGlossaryTerm - queried by GlossaryDAO
HProject - queried by ProjectDAO
HProjectIteration - queried by nothing that I can find (update: removed by https://github.com/zanata/zanata-platform/pull/576)
HTextFlowTarget - queried by TranslationMemoryServiceImpl
TransMemoryUnit - queried by TranslationMemoryServiceImpl

If we're not planning to use (or maintain) the Lucene-related code in these classes, we should remove all their Hibernate Search annotations. Leaving them half-supported makes the code harder to understand (eg why is this entity @Indexed but it doesn't handle disabled records?), wasting development time, and also causes unnecessary indexing at runtime.

See also https://github.com/zanata/zanata-platform/pull/504