Add a way to set fixed tabs width in TabContainer

[me2beats]

Describe the project you are working on

plugins

Describe the problem or limitation you are having in your project

I need tabs with fixed size like here

This is often a better UX practice than tabs headers with different sizes depending on title widths.

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

An ability to set fixed tabs width would solve the problem

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

void set_tabs_width(width:int)

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

It seems, creating a custom container with fixed tab size is the only right option, which is not a few lines.

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

I think this could be useful; this is a good UX practice; many modern GUI frameworks have an option to set tab headers fixed width.

[Calinou]

The Tabs node (but not TabContainer) is supposed to have a minimum tab size theme item, but it doesn't work – see the Tabs Min Size editor setting.

[neruthes]

I am in need of this. Alternatively, we can add an option for removing the ellipses at the end so we can add 100 extra whitespace characters to occupy horizontal space.