Tgra/add class shape

[tgra]

Type of Change

* [x] New domain file
* [ ] Update existing domain file
* [ ] Documentation only

---

Domain

Domain file: class.ttl
Purpose of domain:  nodeshape with rdfs:Class as sh:targetClass
 
Intended use cases:

required for onward transformation of published node shapes with properties that target rdfs:Class - web-id.ttl and issue_tracker.ttl 

---

Shape Details

Shape name(s): ClassShape

Target class / node: rdfs:Class

Files changed: class.ttl

---

Shape Change

* [x] New shape
* [ ] New version of existing shape
* [ ] Non-breaking constraint addition
* [ ] Documentation update

Description:

---

Immutability Confirmation

* [x] Existing constraints were not modified
* [x] Previously valid data remains valid
* [ ] If behaviour changed, a new shape/version was introduced

---

---

Validation

* [x] SHACL validation run
* [ ] Example data tested

Tools used:

---

Reviewer Checklist

* [ ] Immutability respected
* [ ] Targeting is correct
* [ ] Constraints justified
* [ ] Examples match expected behaviour