[CLIENT-3510] Add support for adding a PKI user without a password

[juliannguyen4]

Manual testing
Build artifacts passes
Valgrind shows no mem leaks or errors from these changes
Massif memory usage looks ok

Docs
https://aerospike-python-client--787.org.readthedocs.build/en/787/client.html#aerospike.Client.admin_create_pki_user
https://aerospike-python-client--787.org.readthedocs.build/en/787/aerospike.html#:~:text=tend_interval,-(int
https://aerospike-python-client--787.org.readthedocs.build/en/787/aerospike.html#aerospike.AUTH_PKI
https://aerospike-python-client--787.org.readthedocs.build/en/787/config_provider.html#aerospike.ConfigProvider

Extra changes:

• Add missing documentation for aerospike.AUTH_PKI constant
• Docs: Fix incorrect parameter name "username" by changing it to "user" for Client.admin_{create_user,drop_user,change_password,set_password,grant_roles,revoke_roles}()
• CI/CD: Enable mutual TLS authentication for running the create_pki_user test. Create client certificate and private signing key for the "superuser" user
• Fix invalid usage of nullcontext in tests
• Replace metadata section in dynamic config with version field
• Tend interval must be at least 250 ms now
• CLIENT-3500 Fix seg fault when we run a paginated query with a partition filter and then re-run the same query object with another partition filter that has different "begin" and "count" values
• CLIENT-3543 Support client identifier user agent

Notes:

• Link check job is still failing. It will be fixed before next release

TODO

• Refactor helper function that converts a Python list of strings to a C array of strings.~~ Do this in a future PR

[codecov-commenter]

Codecov Report

Attention: Patch coverage is 91.93548% with 5 lines in your changes missing coverage. Please review.

Project coverage is 82.00%. Comparing base (7256716) to head (875f84b).
Report is 3 commits behind head on dev.

Files with missing lines	Patch %	Lines
src/main/client/admin.c	93.75%	3 Missing ⚠️
src/main/conversions.c	85.71%	2 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##              dev     #787      +/-   ##
==========================================
+ Coverage   81.92%   82.00%   +0.08%     
==========================================
  Files          99       99              
  Lines       14671    14698      +27     
==========================================
+ Hits        12019    12053      +34     
+ Misses       2652     2645       -7     

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.

🚀 New features to boost your workflow:

• ❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.

[dwelch-spike]

Nice! In general this LGTM I just have a few things to run by you in the comments. Let me know when you've had a look.

[dwelch-spike]

LGTM!