fix(guidelines): fix link relations deep links

[Rawezhham176]

Changelog:

Update

• Changed "MUST use absolute URIs for custom link relation types" R100037 to reflect the current implementation of resolvable link relations without namespaces.
• Updated examples of link relation URLs and templated CURIE links to match the current implementation in the OTTO Consumer API Portal. Changes refer to the rules "MUST use absolute URIs for custom link relation types" R100037, "MUST use curied link relation types" R100038 as well as "MUST document link cardinality" R100063.

[BirgitBader]

@maxedenharter0507 and @Rawezhham176
Please specify the changelog entry. For users following a public repository it's hard to grasp what's been done. (Even for me ;-))

I did not review the URL changes - I left that for Max ;-) , but left an inline comment.