[TASK] Use core BE configmanager getPageUid as fallback

This ensures complete compatibility compatibility with CLI commands which fall back to loading root page UID from the root TS record. Before, the behavior of this resolving was a bit too strict but perfect for BE usage - after, the final, custom TS record resolving is replaced with the (only) method the standard BE configmanager normally uses.

Fixes: #668
[TASK] Ensure DateTime field contains executable code

Custom create() method added, allowing presetting of settings (such presets currently not added).
[TASK] Refactor Select field's getItems method
[TASK] Compact logic of ResolveUtility::resolveCurrentPageRecord
[TASK] Compact two conditions in ClipBoardUtility
[TASK] Refactor ResolveUtility to expose overlay resolving as API
[TASK] Refactor ContentAreaViewHelper to smaller units
[TASK] Refactor RecordServiceTest::preparedGet and add tests
[TASK] Do not use VHS ViewHelperUtility
[TASK] Cover Form scope with tests
Merge pull request #669 from NamelessCoder/refactorings

[TASK] Refactorings