WIP: versioning phase 6

conf/core/cache.ccf

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

...a/caosdb/server/database/CacheableBackendTransaction.java

...ackend/implementation/MySQL/MySQLRetrieveFullVersion.java

...abase/backend/interfaces/RetrieveFullVersionInfoImpl.java

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

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

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

...abase/backend/transaction/RetrieveFullVersionHistory.java

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

...rver/database/backend/transaction/RetrieveProperties.java

.../backend/transaction/RetrieveQueryTemplateDefinition.java

...er/database/backend/transaction/RetrieveSparseEntity.java

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

...sdb/server/database/backend/transaction/UpdateEntity.java

...rver/database/backend/transaction/UpdateSparseEntity.java

...java/caosdb/server/database/proto/VersionHistoryItem.java

src/main/java/caosdb/server/entity/DeleteEntity.java

src/main/java/caosdb/server/entity/Entity.java

src/main/java/caosdb/server/entity/EntityInterface.java