Csv2bufr

Bug fix to address bug introduced as part of v0.6.0 (missing data raises an error).

Erroneous error messages removed for data failing QC checks.

Bug fix and default output path

This release provides:
- clearer output from the CLI tool
- default group and user added to the Dockerfile + resulting image.

Bug fixes:
- Empty values in the BUFR templates were not previously detected correctly. This has now been fixed.

This release provides the following updates and breaking changes:

- update to v2.28.0 of ecCodes
- removal of JSON metadata
- simplified mappings
- documentation updates (WMO theming)
- update of `_meta` to be GeoJSON compatible
- cleanup of modules/dependencies
- improved templates
- addition csv2bufr transform as pygeoapi process plugin

This release provides the following updates and breaking changes:

- add extra error logging on station metadata errors
- update message `_meta` to be a GeoJSON
- remove use of JSON station metadata
- use WMO Sphinx theme for docs
- update to json schema for mapping from csv to BUFR.