add export csv delim setting in project setting

[JustusPan]

Problem Description:
When using functions, especially those with multiple parameters, half-width commas are used to separate the parameters.
These half-width commas interfere with Godot's CSV parsing in the exported CSV translation file, causing the translation to not work properly.

Requested Feature:
Godot allows you to select delim in the import tab when importing CSV, which can be any of Comma, Semicolon, and Tab.

Solutions tried:
I tried adding a delim parameter to all get_csv_line and store_csv_line methods in the main_view.gd file (Godot already supports this parameter), I filled them all with "\t", then regenerated the translation CSV using dialogue in Godot and selected Tab delimiter during import, which worked very well.

Since my modification is quite crude, I'm not sure if I considered all situations, so I request that you officially support this feature. Allow users to set the delim used for exporting CSV in Project Settings.

Thank you for this tool!