Fixes some problems introduced by #49917
* Tree used minimum size as a stretch ratio, so it forced a minimum size of 1.
* Minimum size redone, stretch ratio moved to a separate setting
* Fitting to contents was enforced, this is more intuitive, but in many situations this is undesired.
* Added a clip content option for situations where fit to contents does not apply.
* Icon would scroll with the item, making it invislbe if the item is too long.
* Made icon always appear to the right (or left if RTL is enabled) of the visible item space.
Updates rich_text_label so that the built-in documentation can be searched
Previously, it would only find the first result and would not select other results
Renames "_entered" functions to "_submitted"
Renamed to ActionMapEditor as it is more generic and can be used for more than just the InputMapEditor if required.
This also includes a new Event Configuration dialog (previously "Press A key...") which can be used to create and edit InputEvents for any use - like the Project Settings input map, or the Editor Settings shortcuts.
