feat: first iteration of C client library

[codecov[bot]]

Codecov Report

Attention: Patch coverage is 93.23077% with 22 lines in your changes are missing coverage. Please review.

Project coverage is 81.38%. Comparing base (2b3d6cf) to head (05398d5). Report is 6 commits behind head on master.

Files	Patch %	Lines
src/client.c	76.40%	8 Missing and 13 partials :warning:
test/unit/test_client.c	99.00%	0 Missing and 1 partial :warning:

Additional details and impacted files

```diff @@ Coverage Diff @@ ## master #636 +/- ## ========================================== + Coverage 81.21% 81.38% +0.16% ========================================== Files 192 195 +3 Lines 27061 26198 -863 Branches 4943 4660 -283 ========================================== - Hits 21978 21320 -658 + Misses 3445 3281 -164 + Partials 1638 1597 -41 ```

:umbrella: View full report in Codecov by Sentry.
:loudspeaker: Have feedback on the report? Share it here.

[letFunny]

This is not a priority for the time being.