Add option to disable showing the "Show Extreme Games" option

[Seirade]

Is your feature request related to a problem? Please describe.
At the moment, if someone wants to hide the option to show extreme games from showing up in Config, they have to manually edit config.json to change the disableExtremeGames to true.

Describe the solution you'd like
It'd be nice if, from a fresh copy of the Launcher, there was in option to "Disable Extreme Games". This option would only be visible when disableExtremeGames is false. Toggling this option on would hide the "Show Extreme Games" option, and effectively "neuter" itself, since the option would now be set to true.

Describe alternatives you've considered
Another option would be to leave it visible always, but toggling requires a password. However after talking with Colin, it seems that the obscurity is desired so that it's not revealed that the "Show Extreme Games" option can be enabled.

Additional context
This is mainly a quality of life feature to make it slightly easier for parents to disable the option without having to manually edit a file.