Fix/z3fdb bugs

[Ozaq]

Description

Addresses 3 slammer z3fdb issues:

FDB-619, FDB-634, FDB-632

Commits

    Better error on z3fdb view creation error

    When constructing a z3fdb view the build access one grib message to
    establish field size. If this data was not found the exception from FDB
    is passed on. This commit catches and rethrows the exception with a
    error message that is better to understand for users of z3fdb.

    Fixes: FDB-619
---
    Add bounds check to ChunkedDataView::at

    Fixes: FDB-634
---
    Refactor to proper pep8 naming

    extendOnAxis -> extend_on_axis

    Fixes: FDB-632
---

Contributor Declaration

By opening this pull request, I affirm the following:

• All authors agree to the Contributor License Agreement.
• The code follows the project's coding standards.
• I have performed self-review and added comments where needed.
• I have added or updated tests to verify that my changes are effective and functional.
• I have run all existing tests and confirmed they pass.

🌈🌦️📖🚧 Documentation Z3FDB 🚧📖🌦️🌈
https://sites.ecmwf.int/docs/dev-section/z3fdb/pull-requests/PR-226

🌈🌦️📖🚧 Documentation FDB 🚧📖🌦️🌈
https://sites.ecmwf.int/docs/dev-section/fdb/pull-requests/PR-226

[codecov-commenter]

Codecov Report

❌ Patch coverage is 95.77465% with 3 lines in your changes missing coverage. Please review.
✅ Project coverage is 73.55%. Comparing base (8f06994) to head (96f4097).
⚠️ Report is 3 commits behind head on develop.

Files with missing lines	Patch %	Lines
tests/chunked_data_view/test_view.cc	93.47%	3 Missing ⚠️

Additional details and impacted files

@@             Coverage Diff             @@
##           develop     #226      +/-   ##
===========================================
+ Coverage    73.32%   73.55%   +0.23%     
===========================================
  Files          363      363              
  Lines        21976    22044      +68     
  Branches      2259     2260       +1     
===========================================
+ Hits         16113    16214     +101     
+ Misses        5863     5830      -33     

☔ 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.

[tbkr]

Thanks for implementing the error checking. This was needed. The CI is currently failing. Once this has been fixed the PR can be merged.