UI: make our shortcut working from all appropriate places

[Vassiliy-Kudryashov]

Description
Shortcut should work from both editor and project view.
In case our default shortcut 'Ctrl+Alt+U' conflicts with other actions in IDE (actually we don't seem to conflict but definitely share the shortcut with 'Unshelve Sliently' and 'Show UML Popup' actions) we have to provide an alternative.

To Reproduce

1. Select some class or package in Project View
2. Use Ctrl+Alt+U shortcut to create tests

Expected behavior
'Generate tests with UTBot' dialog appears

Actual behavior
Nothing happens

Environment
Test framework: any
Java: 1.8
Mockito: Other packages
Test: Not parametrized