MAINT: Renamed classes and methods

src/main/java/caosdb/server/database/BackendTransaction.java

...end/implementation/MySQL/MySQLRetrieveVersionHistory.java

...tabase/backend/interfaces/RetrieveVersionHistoryImpl.java

.../database/backend/transaction/RetrieveVersionHistory.java

...ver/database/backend/transaction/RetrieveVersionInfo.java

.../caosdb/server/resource/AbstractCaosDBServerResource.java