Implement NSFW Toggle

[inferenceus]

As discussed in the Accrescent Matrix room, if 18+/NSFW content is allowed to be published to Accrescent (there doesn't currently seem to be a policy regarding this), implement a toggle to enable such content for download by users. Such content may include, but is not limited to, violence (usually found in video games) and sexual content (video games, video/streaming apps etc).

The toggle should be disabled by default to protect users who do not wish to view this type of content.

Developers should be required to mark their apps as 18+/NSFW if they contain such content, perhaps via a checkbox in the developer console.