Icon Picker: Improvements, OOTB Property Editor, etc...

[markadrake]

Recommend some changes to the existing icon picker:

• Allow categorization/differentiation between the Umbraco defaults and icons added from other packages.
• How can we define synonyms for icons to make them easier to find in search?
• Expose the icon picker as a property editor that can be used as a data type.
  • Preconfig values:
    • Toggle color visibility (default to black if not visible).
    • Set default color. (Works with/without colors being visible)
    • Set default icon.
• Consider adding an optional icon override to the "block appearance" section once exposed as an OOTB property editor.

[mistyn8]

https://github.com/glombek/umbicosaurus from v8 days...

[bjarnef]

For reference also suggested by @callumbwhyte to relate meta data to icons: #9122

Furthermore in v14/v15 it has a limited set on icon colors.

It may be okay not to have a full set of color spectrum, but with default/light theme and from accessibility point of view I don't think the yellow and pink is useful for tree icons.

Currently I think this just align with the colors used in backoffice for toasts/notifications etc.