revamp Domains

[bansp]

https://standards.clarin.eu/sis/views/list-domains.xq

Things to do:

• make "uncategorized" actually uncategorised, so with the @sortBy either absent or set to empty string
  • basically, accept the fact that metadomains are merely helpful rather than obligatory
• remove the metacategory "Databases", because it's misleading (the "Databases" metacategory should change #349)
• possibly add a "source code" domain (in this way, handle Remove programming languages? #265)
• add domains for experimental data depositions (as in the CH consortium, consult @acraevschi )
• consider renaming "Documentation" (maybe just by adding an attribute), so that it is not confused with Language Documentation, which obviously needs more than one domain; if possible, consult @hannahedeland
• add ML-related domains (does 'data-preparation', 'model-training', 'model-exchange' make sense?); if possible, consult @raspberryjoy
• describe/gloss them better (that is actually a very vague directive...)
• possibly add archeological-data-related domains (DARIAH but also ARCHE, Potential additions to functional domains #291 )
• align with Re3Data content type (re3data domains (contentType) #241)
• make metadomains more than just projections of the sortBy attribute (list the metadomains in domains.xml, with a brief description; constrain the values of sortBy #362 )
• sort out the status of functional domains vis-à-vis Resource Families (reference to resource families? #154 )
• check the link to the SIS:Domains label for potential additional issues
• with each change of the content of the list of domains, synch domains.xml with recommendation.xsd