menutree fixes

This makes menu tree ***less broken*** than it was before. I've never used it so I don't know how exactly it all supposed to work, but at least the admin side renders now. It still has problems though-

| Q             | A
| ------------- | ---
| Bug fix?      | yes
| New feature?  | no
| BC breaks?    | no
| Deprecations? | no
| Tests pass?   | yes
| Fixed tickets | -
| Refs tickets  | -
| License       | MIT
| Doc PR        | -