WIP: [needs design...] New tag selection widget for resources

I made the new tag selection widget for resources. There are multiple parts in it:

• KisWrappableHBoxLayout (layout for labels and the + button)
• ===
• WdgCloseableTagButton (button that represents a tag; can be closed by X at the end)
• WdgAddTagButton (button with [+] that appears at the end of the tag collection; can be used to add new tags from possible tags)
• WdgAddTagsCategoriesButton (button with [+] that appears at the end of the tag collection; can be used to add new tags from possible tags - the same as above, but with categories)
• ===
• WdgTagSelection (widget with everything, including layout and all buttons)
• ===
• KisWdgTagSelectionControllerOneResource - controller for one resource in RM case
• KisWdgTagSelectionControllerBundleTags - controller for tags from multiple resource types in create bundle case

Test Plan

Go to Settings -> Manage Resources -> Create. Press on the [+] button.

(Older screenshot, but shows tags:)

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.