Initial changes for issue 5955 allowing to display selector groups
Allow to add groups
Added an info message when no groups are created and allowed to add
several groups instead of always replacing the first one
Display an info message for a group in case the selector doesn't match
any elements
Allow to fold the different groups
Persist the selector trials across page reloads
Allow to remove the selector trials again
Added selector validation while typing
Immediately update the panel when the DOM structure has changed
Fix display of "No matching elements" message on panel reload
Allow to add invalid selectors
Tightened up Selectors side panel translations and removed old related
CSS files
Adjusted selector editor font
Added missing translations
Merge branch 'issue5955'