Transaction generalizing

[plyhun]

Abstract

Tx entity is widely used in the common code, so has to be generalized into the MDM API as well.

Actions performed:

1. Tx split into general Tx and GraphDBTx. Tx went into mdm-api.
2. DAOAction classes went into mdm-api.
3. BaseTransaction class split into BaseTransaction and GraphDBBaseTransaction. BaseTransaction went into mdm-api.
4. DAOCollection now references *DAOs, not *DAOWrappers. DAOCollection went into mdm-api.
5. All the references to DAOWrappers replaced with ones to DAOs where possible. Otherwise a classcast is used, which will be removed after the field containers are split.

Checklist

General

• Added abstract that describes the change
• Added changelog entry to /CHANGELOG.adoc
• Ensured that the change is covered by tests
• Ensured that the change is documented in the docs

On API Changes

• Checked if the changes are breaking or not
• Added GraphQL API if applicable
• Added Elasticsearch mapping if applicable