Allow disabling of system fonts for extinct languages

[Sunspark-007]

Your system information

• Steam client version: Current
• SteamOS version: 3.5.7
• Opted into Steam client beta?: No
• Opted into SteamOS beta?: No
• Have you checked for updates in Settings > System?: Yes

Please describe your issue in as much detail as possible:

In desktop mode, a large selection of Noto fonts is present in the system fonts section. They cannot be disabled in the font manager due to the immutable nature of the OS. The list is large, and clutters up font menus. It would have been nice if Google had made a single mega-sized unicode font, but this was not to be. So instead, we have individual fonts like Noto Sans Cuneiform and Noto Serif Old Uyghur, etc. Many additional fonts for dead alphabets and languages are present.

Desired is the ability to disable the useless fonts, even if they come back with a system update due to the immutable nature of the OS.

Or just, REMOVE the ones for languages not currently written or spoken. They can easily be re-installed by the user in the personal section, should someone actually desire to use Noto Sans Egyptian Hieroglyphs!

I can assist with identifying which fonts should be removed if the solution chosen is to remove them from the system section, otherwise desired is the feature to disable them.

Steps for reproducing this issue:

1. Attempt to disable a system font in the KDE font management panel.

[missionfloyd]

The write protection can be disabled with sudo steamos-readonly disable