CustomCommand: Allow plugin to expand to all rows in the panel + fixes

[elviosak]

• Added option to expand to all panel rows (only has effect when panel has more than 1 row). Default off, same behavior as before.
• Correctly calculate "max width" when panel is vertical and auto rotate is off (text is horizontal and height will be limited by "max width" from config)
• Removed ProxyStyle, was being used for right eliding text, but it is unnecessary and was preventing multi line output. (Could be re-added if the default middle eliding is annoying, or i can change to just clip the extra text instead of right eliding)
• Reduced button updates during plugin creation and settingsChanged() or when command finishes (if text size doesn't change it won't update the dimensions)

Example with vertical panel with 2 rows and some plugins:

[tsujan]

Please rebase. LXQtCustomCommandConfiguration is cleaned up to conform to other plugins (after recent changes).