Enhance language around spec versioning

[garethsb]

Adding this as an issue here but with the expectation that @AMWA-TV/nmos-architecture-review will move it somewhere more general.

IS-04 and IS-05 say things like:

Versions MUST be represented as complete strings. Parsing MUST proceed as follows: separate into two strings, using the point (.) as a delimiter. Compare integer representations of MAJOR, MINOR version (such that v1.12 is greater than v1.5).

E.g. at https://github.com/AMWA-TV/is-05/blob/v1.1.x/docs/APIs.md#common-api-base-resource

This could be written more clearly everywhere (first MUST doesn't really seem to be a requirement on implementations, whether Nodes or Controllers, and second and third sentence seem overly prescriptive and yet the most important bit is the parenthetical phrase!).

Automated test cases seem tricky too...

[peterbrightwell]

Architecture Review Group review: place on backlog