Exclude "addons"-folder from search

[TheFlamyy]

Godot version: 3.X

The project's search bar is a powerful "tool". You can search for names, extensions etc.
But it gets bloated quickly with scripts and files from your "addons" folder. A project wise option to exclude it from search results would be a good addition.

Example:
You want to find all of your scripts. You have downloaded a few addons. You type ".gd" into the search bar and tons of the addons' scripts appear.

[eon-s]

This for quick open scenes and scripts too.

[Jummit]

I would also like to remove addon files from the project search and the autocompletion of preload.

[TheFlamyy]

Issue has been moved to godotengine/godot-proposals#25