Add human readable tables for source_ids, experiment_ids and licenses

[matthew-mizielinski]

Add the searchable HTML tables. Are there any other fields in this repo that we should include?

[durack1]

activity-id, I suppose the source_id entries will list the institution_id maintained in the MIP-CMOR-tables

[durack1]

This will require GH pages to be turned on - following the same format as the CMIP6_CVs precursors:
https://wcrp-cmip.github.io/CMIP6_CVs/docs/CMIP6_experiment_id.html
https://wcrp-cmip.github.io/CMIP6_CVs/docs/CMIP6_institution_id.html
https://wcrp-cmip.github.io/CMIP6_CVs/docs/CMIP6_source_id.html etc
found in https://github.com/WCRP-CMIP/CMIP6_CVs/tree/master/docs, with https://github.com/WCRP-CMIP/CMIP6_CVs/blob/master/src/jsonToHtml.py used to generate these every PR merge

Ref PCMDI/pcmdi.github.io/#534