Better management of script files list in the script editor

[ArdaE]

Godot version:
3.1.1

Issue description:
Regarding the open script files list in the left pane of the script editor (above the methods list), please add an option to only list script files that meet one of the following criteria:

1. Used by the current scene (attached to any node within the scene)
2. Is a standalone script (not associated with any scene) and was opened by the user at some point
3. Is the currently viewed file in the script editor (because it contains the current line that the debugger stopped on, contains a text search result that the user clicked on, etc.)

So if the option is turned on, whenever the scene tab changes, only the scripts that meet one of the criteria above would be listed among the open scripts. When the option is off, the current behaviour would continue for people who want to see all scripts they've opened at some point.

In any sizeable project, the Scripts Panel ends up containing countless scripts, making it a pointless mumbo jumbo of file names with no association to the currently selected scene. This proposal would fix that.

[ArdaE]

Of course, this option would also enable auto-saving of scripts before they're automatically closed.

[FrederickDesimpel]

Want to put some attention on this again, mainly point 1.

Could be a hierarchy or divider in the script list, or have a second row of tabs under the scene tabs with that scene's scripts as tabs.

I keep having to switch between scenes and scripts and often have to look for the right script, it gets confusing fast.

Another thing that could help is that when a script is selected that scene tab if any is open that uses it is activated, so we at least see the right scene outliner.

[Cerno-b]

In case anyone comes across this post, I think there have been numerous attempts to discuss the organisation of scripts in the godot-proposals repo (possibly more than those):

godotengine/godot-proposals#7838
godotengine/godot-proposals#4457
godotengine/godot-proposals#5314
godotengine/godot-proposals#4081

[Calinou]

Closing in favor of the proposals linked above, as feature proposals are now tracked on the Godot proposals repository.