✨ Add route to allow user to change username

[shnizzedy]

No description provided.

[shnizzedy]

In my response to a question on Slack:

We clearly need better documentation around the intended flow and the status quo. A few relevant points here:

• The /user routes interact with both the User and Profile data models dynamically. Generally, calls to /user/{id} deal with Profiles and calls to /user without {id} deal with the logged in User.
• That screenshot is from the Girder interface which is, as far as I understand for our use cases, intended for development but not for general users (favoring our own interfaces). We haven't been maintaining the Girder interface except for gradually restricting what data are visible there. I suspect we'll eventually pare it all the way down to just a login/logout for the interactive Swagger documentation.
• I think where in the interface a change-username action happens is beyond the scope of this issue, which is to either add a new API route or update an existing route to allow that action to happen through the API.

The screenshot referenced therein:

[shnizzedy]

A point of clarification: we're phasing out userId visibility, so we'll either need to restrict to the logged-in user (eg, https://github.com/ChildMindInstitute/mindlogger-app-backend/blob/ac133722bda67b20e872851a5be62c0ce416b425/girderformindlogger/api/v1/user.py#L387) or use a profile ID or login name to identify the user being updated (eg, https://github.com/ChildMindInstitute/mindlogger-app-backend/blob/ac133722bda67b20e872851a5be62c0ce416b425/girderformindlogger/api/v1/user.py#L164).

[shnizzedy]

Proposed solutions:

#605	#607	#608	#616	📝 Report
PUT /user/{id}	PUT /user/login PUT /user/{id}/login	PUT /user/{id}	PUT /user/login	PUT /user/{id} PUT /userUpdate/{id}

[shnizzedy]

@shnizzedy please confirm that this requested API endpoint is intended for ADMIN user use only, or an ordinary user will be able to change his/her username also?

― #607 (comment)

Any user should be able to change their own username, and I don't think there's any reason for an admin to be able to change another user's username. I'm not even sure if usernames are or should be findable; their main use is just for logging in. All user roles are at the applet level, but usernames (login) are part of the User class.

― #607 (comment)

[WorldImpex]

works per @devbtech