ComponentChooser: Add more default applications

TODO

• Fix section topPadding, probably somewhere in Kirigami. (Reported as a Kirigami.FormLayout issue: https://bugs.kde.org/show_bug.cgi?id=454999)
• Refactor the saveMimeTypeAssociation to a saveMimeTypeAssociations batch for multiple mimetypes at once
• Add a m_mimetypes/getMimeTypes() to ComponentChooser.
• Check in saveMimeTypeAssociation that the application's KService supports the mimetype it is supposed to be assigned to.

The existing default applications are:

• Web Browser
• File Manager
• Email Client
• Terminal Emulator
• Map (added by Volker in !756 (merged) for Plasma 5.24)
• Dialer (added by Kai in !787 (merged) for Plasma 5.24)

This MR adds a few default application settings:

• Text Editor (recommended: Kate)
• PDF Viewer (recommended: Okular)
• Image Viewer (recommended: Gwenview)
• Music Player (recommended: Elisa)
• Video Player (recommended: Haruna)
• Archive Manager (recommended: Ark)

This also:

• Reorders the comboboxes of the default applications
• Changes m_type and type to m_category and category for clarity since those refer to the Category section of the .desktop files
• Formats stuff with clang-format (otherwise git wouldn't let me commit)

Feedback needed:

• I think the page is kinda bare with just a list of comboboxes, what do you think?

Solution: include a button to showcase which mimetypes are associated with the application Solution: in the future, add an extra page to the KCM to add more niche default applications, like chat apps

• Should I be extensive with the mimetype lists?

Solution: no, use a mimetypes list that is common to most apps

Thoughts for the future:

• Software store (recommended: Discover)
• IDE (recommended: KDevelop)
• Archive manager (recommended: Ark)
• Word Processor (recommended: LibreOffice Writer)
• Spreadsheet Editor (recommended: LibreOffice Calc)
• Slide editor (recommended: LibreOffice Impress)
• Chat apps

How it looks now:

(ignore the pink folder, that's from the accent color)

BUG: 454759 BUG: 393812 BUG: 232545 FIXED-IN: 5.26