Replacing QUrl with QString

Right, So I tried to replace QUrl (The ones that did not point to a website), with QString. It worked for the most part, but I had to change a lot of stuff, and even explicitly convert some QUrls to QStrings, because otherwise, the function didn't work as intended, or I would get an error.

Keep in mind that I haven't replaced all of the QUrls yet, hence the "WIP"

Test Plan

There's no damn test plan in this merge request, because this is mostly code based

Formalities Checklist

• I confirmed this builds.
• I confirmed Krita ran and the relevant functions work.
• I tested the relevant unit tests and can confirm they are not broken. (If not possible, don't hesitate to ask for help!)
• I made sure my commits build individually and have good descriptions as per KDE guidelines.
• I made sure my code conforms to the standards set in the HACKING file.
• I can confirm the code is licensed and attributed appropriately, and that unattributed code is mine, as per KDE Licensing Policy.