Qt/Patches: Improve patch validation and patch creator

[Megamouse]

Backend:

• Validate yml patch offset values (prevent overflow)
• Do not allow empty patch names
• Fix logging for locations of node iterators (previously "location: invalid node")
• Improve location logging of some other invalid patch nodes

Frontend:

• Add validator to patch creator bottom offset line edit (updates depending on patch type)
• Add clear buttons to patch creator bottom line edits
• Highlight faulty lines in patch creator
• Fix some memory leaks regarding QValidators

Caveats:

• The table itself doesn't validate the offset input, but at least you now get better feedback in general.

fixes #14169

[elad335]

File path as of recently can also be typed in offset, this should reflect that.