Implement a RichTextEdit Control

[CsloudX]

Describe the project you are working on

NO-GAME application

Describe the problem or limitation you are having in your project

I wish my user who don't know bbcode syntex can custom a panel to show bbcode.

Describe the feature / enhancement and how it helps to overcome the problem or limitation

There was RichTextLabel can show bbcode, and I need a RichTextEdit for edit like Qt's QTextEdit

Describe how your proposal will work, with code, pseudo-code, mock-ups, and/or diagrams

Implement a RichTextEdit, it have below methods:

set_bbcode(text)
get_bbocde()
set_select_bold(yes:bool)
set_select_underline(yes:bool)
set_select_link_to(url)
...

If this enhancement will not be used often, can it be worked around with a few lines of script?

I don't know how to implement it by GDScript

Is there a reason why this should be core and not an add-on in the asset library?

The RichTextEdit show a basic Control

[Calinou]

Duplicate of #1781.