Implement encoding for currently known CAMS fields

[tweska]

This PR implements encoding for fields mapped in ecmwf/multio#245

[codecov-commenter]

Codecov Report

❌ Patch coverage is 10.71429% with 25 lines in your changes missing coverage. Please review.
✅ Project coverage is 62.27%. Comparing base (03c7e0f) to head (e5774b6).

Files with missing lines	Patch %	Lines
...kit/mars2grib/backend/deductions/firstWavelength.h	0.00%	8 Missing ⚠️
...backend/concepts/composition/compositionEncoding.h	0.00%	6 Missing ⚠️
.../backend/concepts/composition/compositionMatcher.h	37.50%	5 Missing ⚠️
src/metkit/mars2grib/backend/deductions/chemId.h	0.00%	4 Missing ⚠️
...it/mars2grib/backend/concepts/level/levelMatcher.h	0.00%	1 Missing ⚠️
...ackend/concepts/point-in-time/pointInTimeMatcher.h	0.00%	1 Missing ⚠️

Additional details and impacted files

@@             Coverage Diff             @@
##           develop     #184      +/-   ##
===========================================
- Coverage    62.33%   62.27%   -0.07%     
===========================================
  Files          303      304       +1     
  Lines        11601    11615      +14     
  Branches      1036     1035       -1     
===========================================
+ Hits          7232     7233       +1     
- Misses        4369     4382      +13     

☔ 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.

[tweska]

I seem to have broken something with this PR. I'll keep this as draft until I figure out what.

It was a ) in the wrong position... :^/

[MircoValentiniECMWF]

Now seems ok. Thanks