* Clean up parent alignment code
* Don't hide widget if it currently has focus
* Use Qt::Tool window type on macOS as well. This prevents the popup help from hiding to the background if the main window has focus.
* Fixes#2814
This allows `t:word` instead of `title:word` and `p:word` instead of `password:word`, and so on. The rule is that an abbreviated name expands to the first field name that starts with it, with exceptions
`u:` expanding to `username:` instead of `url:` and `pw:` expanding to `password:`.
* Support ! modifier (same as '-')
* Create reusable PopupHelpWidget as self-contained popup that can
be positioned around a parent widget and will follow the movement
and sizing of the window
* Eliminated KEEPASSXC_MAIN_WINDOW macro and replaced with
getMainWindow() function
* Add tests to cover search help show/hide
