Remove python-keycloak

[FedericoNegri]

Background:

• python-keycloak versions < 3.9.1 depend on python-jose which in turn depends on ecdsa, which has safety vulnerabilities
• because of the above, python-keycloak >= 3.9.1 replaced python-jose with jwcrypto which is LGPL.

I propose to get rid of python-keycloak as a PyHPS dependency (we'd only keep using it for tests). The package was only used in the AuthApi as a convenience to query/create/modify/delete users as well as query their groups and roles.

Since by default HPS users do not have the realm management manage-users role, it seems just misleading to expose the create/modify/delete users endpoints. I therefore removed those and rather added an example in the doc showing how to use the KeycloakAdmin client from python-keycloak to do so.

Nightly build run with Python 3.9 - 3.12 tests: https://github.com/ansys/pyhps/actions/runs/8158129451

Breaking change

ansys.hps.client.auth.authenticate moved to ansys.hps.client.authenticate to avoid circular dependencies

[codecov]

Codecov Report

Attention: Patch coverage is 94.11765% with 2 lines in your changes are missing coverage. Please review.

Project coverage is 93.36%. Comparing base (cd4f63d) to head (4dab70a).

Files	Patch %	Lines
src/ansys/hps/client/auth/api/auth_api.py	93.54%	2 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #352      +/-   ##
==========================================
+ Coverage   92.82%   93.36%   +0.54%     
==========================================
  Files          61       61              
  Lines        2258     2232      -26     
==========================================
- Hits         2096     2084      -12     
+ Misses        162      148      -14     

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[PipKat]

@FedericoNegri Only two comments, with only one of those being a correction! This approval is only on doc content--but what you did was excellent. I've never only had one suggested correction, even on PRs much smaller than this one!

[FedericoNegri]

@FedericoNegri Only two comments, with only one of those being a correction! This approval is only on doc content--but what you did was excellent. I've never only had one suggested correction, even on PRs much smaller than this one!

@PipKat your comment made we wonder and I realized I forgot to include the new "managing users" doc guide! please review this one https://github.com/ansys/pyhps/pull/352/files#diff-f835861f0b7fc9c9c1098462eb63089cd78a308d47e973efa1fb1037eaaf98a9, I'm sure you'll have more corrections :-)

[PipKat]

Minor edits suggested.