extra metadata dict, initialized inside `from_owl_uri`

[burnout87]

To start tackling https://github.com/oda-hub/dispatcher-plugin-nb2workflow/issues/53

[codecov[bot]]

Codecov Report

Attention: Patch coverage is 94.73684% with 1 line in your changes missing coverage. Please review.

Project coverage is 62.36%. Comparing base (6f20aa8) to head (453b374). Report is 8 commits behind head on master.

Files	Patch %	Lines
cdci_data_analysis/analysis/parameters.py	94.73%	1 Missing :warning:

Additional details and impacted files

```diff @@ Coverage Diff @@ ## master #697 +/- ## ========================================== + Coverage 62.34% 62.36% +0.01% ========================================== Files 50 50 Lines 8950 8957 +7 ========================================== + Hits 5580 5586 +6 - Misses 3370 3371 +1 ```

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[burnout87]

example of using the label entry inside the extra_metadata entry of the object returned from the reprJSONifiable function

[burnout87]

with the group entry inside the extra_metadata

[burnout87]

These screenshots have been generated using the notebook on my repository:

https://gitlab.renkulab.io/gabriele.barni/photoz-euclid/-/blob/master/Run_Phosphoros_preComputedMG.ipynb

In particular, the following parameters have been grouped together:

• column_name_MW_EBV, column_name_RA and column_name_DEC - group: "Milky Way Extinction"
• column_name_Ztrue, ZP_correction and PDZ_output - group "Redshift"

As a test, I also created the group "File group test" with the parameters catalog_URL and catalog_string