feat(edint-aparcamiento): add 5 candidate models for parking

[albertoabellagarcia]

Summary

Translates the EDINT Parking Ontology (v0.1.0) from
https://github.com/EDINT-Ontologia/edint-ontologia-aparcamiento — on-street
and off-street public/private parking, fees, individual spots, and spot
groupings by permit type or vehicle type. Closely related to
edint-infraestructura (Parking subClassOf Facility, explicitly stated by
the source: "Parking facilities are part of the city's infrastructure...
their access points are represented as a relationship to the
infrastructure's sensor representation"), edint-zona-regulatoria
(RegulatedParkingZone is one of its 22 RegulatedZone subtypes), and
edint-censo-vehiculos (reuses its VehicleType/VehiclePermitType
controlled vocabularies).

Five entities

• Parking: collapses the source's two concrete subclasses
  (OnStreetParking/OffStreetParking) into one entity with a parkingType
  discriminator — bare Parking is never directly instantiated in the
  source's own real example data, and OnStreetParking's only distinguishing
  property (isPartOfZone) is small enough to keep as an always-optional
  field rather than a second entity type. Inherits edint-infraestructura's
  full Facility property set, confirmed by the source's own real examples
  using several of them directly (belongsTo, containsFacility,
  hasInfrastructureType, hasObservationPoint, hasRegisteredOwner,
  address, openingHours).
• ParkingFee, ParkingSpot: thin entities, no source-declared
  properties of their own (same treatment as edint-infraestructura's
  ObservationPoint/edint-zona-regulatoria's RegulatedZone/
  CadastralProperty).
• ParkingSpotsByPermitType, ParkingSpotsByVehicleType: group
  individual spots and carry the vocabulary-backed enums.

All 5 examples are grounded in the source's own real examples/example.ttl
(5 real Madrid/Zaragoza parking instances).

Two source ontology bugs found, worked around rather than copied literally

• permitType's rdfs:domain is declared as ParkingSpotsByVehicleType,
  not ParkingSpotsByPermitType — almost certainly a copy-paste error given
  the property's own name and comment ("group of places by TYPE OF PERMIT").
• vehicleType has no rdfs:domain declared at all.

Copying either literally would produce a nonsensical schema
(ParkingSpotsByVehicleType with a permitType property and no
vehicleType anywhere), so both are assigned per their evident intent
instead. Flagged for the EDINT maintainers, not silently papered over.

⚠️ Known issue, not resolved here (see standard-metadata.yaml)

Same pattern as RegulatedZone/Vehicle in prior PRs: edint-infraestructura
already has its own thin Parking entity from its first translation pass
("modeled as a thin Facility specialization... no attributes of its own").
This candidate's much fuller Parking reuses the same entity type name with
a different property set — a real NGSI-LD type collision, left unresolved
here per the same reasoning already applied to the two prior cases (most
likely resolution: replace the thin stub with this one).

Testing

• All schema.json/context.jsonld/example files parse as JSON, all 5
  example.json validate against their own schema.json.
• standard-metadata.yaml parses as YAML.
• Candidates index regenerated.

Note: based on current master, which doesn't yet include the still-open
#6 (edint-zona-regulatoria) or #7 (edint-censo-vehiculos) — no dependency
between any of them.