Add versioning to the Cadl Rest library

[mikekistler]

The Cadl Rest library should define versions so that a versioned Cadl file can explicitly specify the Rest library version for each API version with @useDependency.

[markcowl]

handle with: https://github.com/Azure/cadl-azure/issues/2332

[markcowl]

Closing as duplicate for https://github.com/Azure/cadl-azure/issues/2332

[mikekistler]

@markcowl Does this mean that versioning of the REST library is definitely going to be done as part of Azure/cadl-azure#2332? This is not clearly stated in either the issue or the proposed design.

I ask because we might choose not to do it there but may want to do it for other reasons.

I'm going to reopen this -- just so it doesn't get lost -- until we have settled on the design for 2332 and decided to version REST as part of that.

[markcowl]

Discussion here: https://gist.github.com/markcowl/ac8eea262f670254a948dc8ef2ecfba4

[markcowl]

Takeaways from discussion:

• Generally positive about versioning these libraries
• Consuming libraries should not require useDependency, and the behavior without dependency pinning should be as expected (latest) and well-defined
• Need to be explicit about problematic versioning decorations for consuming libraries with pinned and unpinned versions