MAINT: Refactoring

src/main/java/caosdb/server/accessControl/UserSources.java

.../database/backend/transaction/DeleteEntityProperties.java

...aosdb/server/database/backend/transaction/DeleteFile.java

...rver/database/backend/transaction/DeleteSparseEntity.java

...osdb/server/database/backend/transaction/GetChildren.java

...er/database/backend/transaction/GetDependentEntities.java

.../server/database/backend/transaction/GetFileIterator.java

...osdb/server/database/backend/transaction/GetIDByName.java

...er/database/backend/transaction/InsertEntityDatatype.java

.../database/backend/transaction/InsertEntityProperties.java

...aosdb/server/database/backend/transaction/InsertFile.java

.../server/database/backend/transaction/InsertLogRecord.java

...rver/database/backend/transaction/InsertSparseEntity.java

...erver/database/backend/transaction/RegisterSubDomain.java

...osdb/server/database/backend/transaction/RetrieveAll.java

...tabase/backend/transaction/RetrieveAllUncheckedFiles.java

...erver/database/backend/transaction/RetrieveDatatypes.java

...rver/database/backend/transaction/RetrieveFullEntity.java

...erver/database/backend/transaction/RetrieveLogRecord.java

.../server/database/backend/transaction/RetrieveParents.java