Rearranged node expression (meta) classes and added the current funct…

[HolgerKnublauch]

…ions to shnex.ttl

sh:Expression/NodeByExpression and annotations were just moved around within the document

This is quite geeky stuff due to the meta-levels:

• The metaclasses such as sh:NamedParameterExpressionFunction
• The actual node expression functions are then instances of sh:NamedParameterExpression, these declare the parameters such as sh:filterName and sh:nodes
• The instances of those are the blank nodes (with values for sh:filterShape), although their rdf:type is usually never asserted

I hope I got these metalevels correct, so please double check anyone :)

Closes #504

• See this document rendered online here

[TallTed]

No obvious issues, to my eye.

[HolgerKnublauch]

I would appreciate some approval of this PR because it is blocking other PRs that also require edits to the shnex.ttl file. @recalcitrantsupplant @simonstey @robert-david

[recalcitrantsupplant]

Looks good to me. My understanding here is the spec defined named parameter functions are both instances of sh:NamedParameterExpressionFunction, and also subclass sh:NamedParameterExpression, which enables explicit parameter linking from the key parameters (sh:Parameter), to the function using rdfs:domain.

[HolgerKnublauch]

Thank you. It is possible that we revisit the metaclasses, but at least we now have the URIs and parameter declarations in TTL form.