[Folder Color] Remove folder-custom and user-custom folder color

[SmartFinn]

Since folder-color 0.3.1 (6 May 2023) stops to support custom color. See costales/folder-color@7aafcba

Unfortunately, the current (22.04) and previous (20.04) Ubuntu LTS releases still uses the older version. That's may break user's experience.

[mjkim0727]

How about to add KDE ColorScheme variant?

[SmartFinn]

@mjkim0727 it's maybe an option, but I don't want to add it manually. It should be a script that convert folder-blue-* to folder-chameleon-* to avoid extra effort when a new folder icon will be added.

[mjkim0727]

I added this variant.