Add support for keepalive

[hmpf]

Closes #62, probably

https://stackoverflow.com/questions/12248132/how-to-change-tcp-keepalive-timer-using-python-script

[sonarcloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
No data about Coverage
0.0% Duplication on New Code

See analysis details on SonarCloud

[github-actions]

Test results

    3 files      3 suites   41s ⏱️
  66 tests   66 ✔️ 0 💤 0 ❌
198 runs  198 ✔️ 0 💤 0 ❌

Results for commit 9e11dac.

[codecov]

Codecov Report

Attention: Patch coverage is 68.96552% with 9 lines in your changes missing coverage. Please review.

Project coverage is 70.23%. Comparing base (ddfbd8c) to head (aeabe20).
Report is 11 commits behind head on main.

Files	Patch %	Lines
src/zinolib/utils.py	72.22%	5 Missing ⚠️
src/zinolib/ritz.py	63.63%	4 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main      #63      +/-   ##
==========================================
- Coverage   70.49%   70.23%   -0.27%     
==========================================
  Files          13       13              
  Lines        1427     1458      +31     
==========================================
+ Hits         1006     1024      +18     
- Misses        421      434      +13     

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

[hmpf]

After help with experimentation with curitz I have added keepalive to the protocol socket (on 8001) as well.