SF-3830 Remove PushAuthUserProfile and basic authentication

[pmachapman]

This PR removes that pushAuthUserProfile JSON-RPC endpoint which was previously used by Auth0.

@Nateowami Can you please check whether this endpoint is still used by Auth0 on QA and Live? (I do not have access to do this, but I have checked the HTTP logs on live, and cannot see the User RPC controller being called by Auth0, as far as I can see). To do this:

1. Open Auth0
2. In the left hand menu, select Actions, then Triggers.
3. Click post-login.
4. Ensure that "Sync user profile with xForge backend" is not present in the flow diagram.

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This change is 

[codecov]

Codecov Report

❌ Patch coverage is 40.00000% with 6 lines in your changes missing coverage. Please review.
✅ Project coverage is 80.99%. Comparing base (e5df661) to head (a6411a5).
✅ All tests successful. No failed tests found.

Files with missing lines	Patch %	Lines
src/SIL.XForge/Controllers/UsersRpcController.cs	37.50%	5 Missing ⚠️
...XForge/Services/AuthServiceCollectionExtensions.cs	0.00%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #3961      +/-   ##
==========================================
+ Coverage   80.92%   80.99%   +0.07%     
==========================================
  Files         637      637              
  Lines       41245    41193      -52     
  Branches     6721     6700      -21     
==========================================
- Hits        33376    33365      -11     
+ Misses       6814     6786      -28     
+ Partials     1055     1042      -13     

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[Nateowami]

@Nateowami reviewed 18 files and all commit messages, and made 3 comments.
Reviewable status: all files reviewed, 1 unresolved discussion (waiting on pmachapman).

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src/SIL.XForge/Controllers/UsersRpcController.cs line 44 at r1 (raw file):

    /// login to ensure the user profile is up to date.
    /// </summary>
    public async Task<IRpcMethodResult> PullAuthUserProfile()

Concerning that this has no exception reporter. Not part of this change but if you want to sneak it in I'll re-review it. (Or a separate PR).

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src/SIL.XForge/Controllers/UsersRpcController.cs line 55 at r1 (raw file):

    /// </summary>
    /// <param name="primaryId">The primary identifier.</param>
    /// <param name="secondaryId">The secondary identifier.</param>

We're documenting the parameters for the method you're not allowed to use (and about to fully rip out)? I guess there's nothing strictly wrong with that...