Replace internal links between Commonalities documents with relative links to stay within the same release tree / fork / release package

[jpengar]

Problem description

Commonalities documents in the repository contain links/references to each other, written as fully qualified URLs pointing to the main branch of Commonalities.

A reader within a release tree would jump out of the tree into a potentially incorrect version. The same is true for someone who has downloaded the release package (zip file) of Commonalities.

Expected behavior

Use - as recommend by GitHub - relative links instead.

e.g.
https://github.com/camaraproject/Commonalities/tree/main/artifacts/camara-cloudevents in Commonalities/documentation
/API-design-guidelines.md document to be replaced with /artifacts/camara-cloudevents (link relative to the repository root).

Alternative solution

N/A

Additional context

This issue corresponds to the same problem raised in the ICM WG at camaraproject/IdentityAndConsentManagement#187 and fixed in ICM r0.2.0-rc.2.

[PedroDiez]

I am generating this PR in this week. Expected to have at least for 14th August