Recommend a taxonomy for theme values

[AlasdairGray]

Is your feature request related to a problem? Please describe.
Currently there is no recommendation for values to use to state the theme of a data asset.

Describe the solution you'd like
Eventually the cross-government taxonomy by the master and reference data working group should be used. However, in the meantime an enumeration based on the data.gov.uk values could be defined. When the taxonomy is available to be used, these could be mapped across.

The enumeration would be defined as

  ThemeValues:
    permissible_values:
      BUSINESS_AND_ECONOMY:
        meaning: https://www.data.gov.uk/search?filters%5Btopic%5D=Business+and+economy
        description: Small businesses, industry, imports, exports and trade
      CRIME_AND_JUSTICE:
        meaning: https://www.data.gov.uk/search?filters%5Btopic%5D=Crime+and+justice
        description: Courts, police, prison, offenders, borders and immigration
      ...

I included the meaning in the above as we are currently using those URIs in the Data Marketplace but users don't find those URIs very meaningful.

Describe alternatives you've considered
A variety of other taxonomies were considered in the Data Marketplace research but none found to be suitable.

[cyberdudeuk]

@richclarke-ho linked to question in KHub.net