This PR extracts the `SemanticVersion` out of `util` and into its own
`SemanticVersion` crate.
This allows for making use of `SemanticVersion` without needing to pull
in some of the heavier dependencies included in the `util` crate.
As part of this the public API for `SemanticVersion` has been tidied up
a bit.
Release Notes:
- N/A
