WIP: MAINT: refactor retrieve properties (move backend-logic to backend)

src/main/java/org/caosdb/server/CaosDBServer.java

.../java/org/caosdb/server/accessControl/ACMPermissions.java

.../database/backend/implementation/MySQL/DatabaseUtils.java

...tabase/backend/implementation/MySQL/MySQLGetAllNames.java

...end/implementation/MySQL/MySQLInsertEntityProperties.java

...backend/implementation/MySQL/MySQLInsertSparseEntity.java

...tabase/backend/implementation/MySQL/MySQLRetrieveAll.java

.../backend/implementation/MySQL/MySQLRetrieveDatatypes.java

...se/backend/implementation/MySQL/MySQLRetrieveParents.java

.../implementation/MySQL/MySQLRetrievePasswordValidator.java

...backend/implementation/MySQL/MySQLRetrieveProperties.java

...ckend/implementation/MySQL/MySQLRetrieveSparseEntity.java

...abase/backend/implementation/MySQL/MySQLRetrieveUser.java

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

...backend/implementation/MySQL/MySQLUpdateSparseEntity.java

...er/database/backend/implementation/MySQL/Replacement.java

...er/database/backend/interfaces/RetrieveDatatypesImpl.java

...rver/database/backend/interfaces/RetrieveParentsImpl.java

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

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