[RTL] Add support for image dynamic updating, padding, tooltips and size in percent.

[bruvzg]

• Adds method to update RTL images without changing the text.
• Adds support for small image padding.
• Adds support for image size in percent of control width.

RTL only part of #69751

[KoBeWi]

Functionality-wise looks ok.

I wonder if there is a simpler way to make update_image() than having to call a method with 7 unused arguments (in case you want to change 1 thing); it's likely the most efficient/intuitive way. The other solution I could think of is replacing arguments with Variant array that has to be filled depending on the mask, but that would be more error-prone.

Another concern is parameter creep in add_image() 🙃 It can't be solved without named arguments though.

[fire]

There is some changes to be rebased @bruvzg

[akien-mga]

The full list of parameters is starting to be quite convoluted, that will be an awkward API to use IMO.
Struct support would be great here, passing a configuration struct with selected optional members defined would probably be better.

[akien-mga]

Needs rebase, otherwise seems good to me.

[akien-mga]

Thanks!