Provide declarative schema features to entity manager

[bohdan-harniuk]

Description (*)
What was done:

1. Column Attributes extracted to the enum type, added default values for them
2. Code refactoring after ColumnAttributes enum was added
3. Added possibility to create expected in the generators columns data from entity properties data
4. Added test coverage for the new feature
5. Code refactoring in the related files
6. Testing in the local env.

Results:

Contribution checklist (*)

• Pull request has a meaningful description of its purpose
• All commits are accompanied by meaningful commit messages
• All new or changed code is covered with integration/functional tests (if applicable)
• All automated tests passed successfully (all builds are green)