Revise conformance section

[VirginiaBalseiro]

No description provided.

[csarven]

Use the Conformance sections from https://solidproject.org/TR/protocol#conformance or https://solidproject.org/TR/notifications-protocol#conformance as template.

1. Normative and Informative Content -- this section can be copy/pasted for starters.
2. Specification Category -- copy/paste but have a look at the concepts under http://www.w3.org/ns/spec#SpecificationCategory .
3. Classes of Products -- work on this section alongside the Terminology section ( Add Terminology section #21 ). Reuse terms from the Terminology section. Have a look at http://www.w3.org/ns/spec#ClassesOfProducts to reuse but it should probably be new/specific concepts where the Spec Terms' concept could be a broadMatch. See notifications-protocol's source
4. Interoperability -- pair/set of classes of products that are intended interop.

If this section is nailed down well, the rest of the spec will "write itself"(TM). I promise! :) There'll surely be revisions on the concepts and descriptions, but everything will make a lot of sense. Seeing the spec as it truly is.

(I'll detail the above in solid/specification CONTRIBUTING.md later)