Add ogc.osc.prov-processing-step: PROV profile for a single geospatial processing step

[nsnarayanam]

D104 (Aganitha) contribution toward Activity 1. Supersedes #13, which was built from an earlier branch — same content plus the JSON-LD bindings below.

A profile of ogc.ogc-utils.prov constrained to a single geospatial processing step. Adds a required processType property linking the step to a registered process type - the link PROV-O and OGC API - Processes Part 5 (26-038) do not themselves provide, and the point where the profile-plus-register pattern closes.

Inputs and outputs are entity references per the PROV-O object model; roles are carried in qualifiedUsage. Both examples validate locally (2/2).

Design question rather than a settled call: processType is bound to dct:type so the value resolves as a governed concept rather than a plain string, following the steer not to mint terms where existing ones will do. A dedicated ospd: property would be more precise than "type" — happy to change if the group prefers that. Worth deciding once rather than per-block.

parameters is deliberately left unbound in the context: how parameters should be typed depends on whether process types are registered coarsely or as parameterised subtypes, which is still open.

Process-type URIs are placeholders pending D110/D111.

Notes:

• Built with the EarthCODE example refs patched locally (see Build fails: broken example URL in ogc.osc.geodcat-stac-earthcode.experiments #11), since the
  master build currently fails on them. Those patches are not included.
• Conflicts are on build-devel.sh and create-clean-pr.sh only — scaffolding,
  not content. The substantive addition is _sources/prov-processing-step/.