reuse props from `org, rov`

This is a sub-issue of https://github.com/OP-TED/ePO/issues/295, listing some specific props that can be reused.

ePO reuses org:Organization, but defines its own props for some that can be found in org and rov (aka regorg). Since both of these are EU core vocabs and published by OPOCE, I think they should be reused to the max.

epo:registeredAddress: consider org:hasRegisteredSite (there's also org:hasPrimarySite). Site is not quite the same as Address but I got advice from Maxx Dekkers that it's ok to collapse them (as we did in euBusinessGraph
epo:hasLegalFormType: use rov:orgType, and use skos:Concept instead of Literal
epo:hasOrganisationUnit: use org:hasUnit (with inverse org:unitOf)
epo:hasLegalName: use rov:legalName. Also, "cardinality 1" is wrong because companies in some countries have several legal names in several official languages
epo:hasMainClassification: is not attached to any class! Consider using rov:orgActivity
- "The activity of a company should be recorded using a controlled vocabulary expressed as a SKOS concept scheme. Several such vocabularies exist, many of which map to the UN's ISIC codes. Where a particular controlled vocabulary is in use within a given context, such as SIC codes in the UK, it is acceptable to use these, however, the preferred choice for European interoperability is NACE".
- In your case you use CPV for classification: I think that's ok with the intent and description of rov:orgActivity

This reuse can spare you some modeling errors (eg #402) or give good ideas (eg #403)

OP-TED / ePO

reuse props from `org, rov` #404