chore: move hof under r/leon

[leohhhn]

Description

Moves r/demo/hof under r/leon. After discussing internally, we should start utilizing personal namespaces as much as possible.

cc @moul

Contributors' checklist...

• Added new tests, or not needed, or not feasible
• Provided an example (e.g. screenshot) to aid review or the PR is self-explanatory
• Updated the official documentation or not needed
• No breaking changes were made, or a BREAKING CHANGE: xxx message was included in the description
• Added references to related issues and PRs
• Provided any useful hints for running manual tests

[moul]

Maybe not "as much as possible," but at least "more" for now. :)

By the way, this PR should partially "break" the portal loop for some addpkged r/xxx/home. However, that's fine; it will help us complete the history rewrite process for the portal loop and gnodev that we're currently working on. #3059