Add styling json file - #14058

Looking good!
I am not convinced by my own opinion, but what do you think of the structure:
/styles/themes/{dark,light}.json ?
Are dark/light considered styles or themes?
And in the future we will add style objects, how do these fit into the folder structure?
Would also love @eilskra 's opinion!

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 91.81%. Comparing base (d9fe003) to head (0fc52e1).
⚠️ Report is 6 commits behind head on main.
✅ All tests successful. No failed tests found.

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we currently have the manager.py which is the theme manager that is responsible for translating the json for qt to be able to processed. So perhaps the whole folder should be restructured in some way.

perhaps something like the following, where the future .qss.in file that applies the styling can be added inside the qss_styling folder, in case we want to have one file per component. So f.eks

Additionally, we can drop the qss_styling folder as of now and just place the .qss.in file inside the styling folder.

@SAKavli @eilskra

I vote either themes or maybe color_schemes?
e.g /styles/themes/{dark,light}.json

Components could maybe just go under maybe style_sheets or something, maybe something along the lines of:

styles/
-- color_schemes/
---- {dark,light}.json
-- style_sheets/
---- qss.in 

perhaps something like the following, where the future .qss.in file that applies the styling can be added inside the qss_styling folder, in case we want to have one file per component. So f.eks

Or like that, I vote this 👍

Merging this PR will not alter performance

✅ 36 untouched benchmarks

_{Comparing add-styling-json-file (0fc52e1) with main (793ddcd)}