Resource naming cardinality

[oyron]

@Qif-Equinor and others have proposed to include guidelines on resource naming cardinality in the API Strategy. From Qiang's PR:

Resource naming

A resource name should clearly indicate the cardinality by using plural nouns for collections, and an instance id for a member of that collection. For example, to get info on well 1234:

GET .../wells/1234

If a relation can only exist within another resource, then append the sub resources to the path. For example: since a well can have multiple well logs, the URL to get a ROHB log for 1234 would appear as follows:

GET .../wells/1234/logs/rohb
```https://github.com/Qif-Equinor/api-strategy.git