Move rich text implimentation as default text renderer

[Shadowblitz16]

Describe the project you are working on

Spaceship Game

Describe the problem or limitation you are having in your project

I would like to use ui elements with rich text effect depending on the ui state

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

Move rich text to be the default text renderer and add custom rich text effects to control and label3d.
Each control state would have the ability to add text overloads.
For example button could have different rich text based on normal, pressed, hovered, focused, disabled

This allows us to have way more control over text in godot

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

see last

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

This can be worked around in cases like buttons which you can just add a child but doesn't if it's something like tab container which is a composite control

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

Rich text is already part of core but it only works as a separate label node.

[Zireael07]

Text in Godot can already be performance heavy, and RTL is heavier than Label