feat: add user creation to users list page

[davwheat]

Supersedes #2998

Progresses #3742

Changes proposed in this pull request:

• adds new user creation modal to Admin
• adds button to open this on the users page

Screenshot

Necessity

• Has the problem that is being solved here been clearly explained?
• If applicable, have various options for solving this problem been considered?
• For core PRs, does this need to be in core, or could it be in an extension?
• Are we willing to maintain this for years / potentially forever?

Confirmed

• Frontend changes: tested on a local Flarum installation.
• Backend changes: tests are green (run composer test).
• Core developer confirmed locally this works as intended.
• Tests have been added, or are not appropriate here.

[luceos]

Do we want to allow setting a password by default? Wouldn't it make more sense to create a temporary one instead? And then hook into the password reset logic?

[davwheat]

I think both are valid options, and I was thinking about that myself.

Maybe an option to "force user to reset password to log in"? Question is whether we want to automatically fire the reset pwd email or just state that the user should reset their own password?

Or should we have a separate "someone's made an account for you on xyz", but that's straying into extension territory imo.

[davwheat]

I've opted to generate a random password on the client-side and provide that, but I do wonder if it's better to generate it in the backend and automate the forgotten password email instead? But I feel a forgotten password for a new user on a site they haven't used yet would be very confusing.

[imorland]

@davwheat what's the situation here? Do you have time to complete these changes so this can be merged, or shall we tackle it?

[davwheat]

Someone else can take it, if they'd like. I don't have the time this week or next.