[#2221] Fix klant creation with e-suite

[pi-sigma]

• Make sure Klant is created via e-suite on user login
• Replace API specs with e-suite compatible versions
• Change default on OpenZaak and OpenKlant config to not use RSIN
• Refactor tests + mocks

Taiga: #2221

[codecov-commenter]

Codecov Report

Attention: Patch coverage is 92.30769% with 7 lines in your changes are missing coverage. Please review.

Project coverage is 95.05%. Comparing base (2e8d47f) to head (e5cb565).

Files	Patch %	Lines
src/open_inwoner/openklant/clients.py	75.86%	7 Missing ⚠️

Additional details and impacted files

@@             Coverage Diff             @@
##           develop    #1123      +/-   ##
===========================================
- Coverage    95.06%   95.05%   -0.02%     
===========================================
  Files          931      933       +2     
  Lines        32947    33009      +62     
===========================================
+ Hits         31322    31377      +55     
- Misses        1625     1632       +7     

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[pi-sigma]

By default, requests_mock forces query params to be lower case (see https://requests-mock.readthedocs.io/en/latest/knownissues.html). I thought it would be good to change that, since whether or not query params are considered case sensitive is not settled by RFC; it seems to depend on the application. We have other tests (CaseListViewTests) that could also be updated.

[Bartvaderkin]

This could ideally do some checks to see if the bit looks like a UUID.

[stevenbal]

Tested it just now, works both for BSN and KVK 👍