Add support for semver suffixes (prerelease + build metadata)

[kMutagene]

see https://semver.org/#spec-item-9

Needed for adding distinctions especially for specification validation, where the package version should be equal to the specification version, but the specs themselves often have prerelease suffixes (e.g. 2.0.0-draft)

[kMutagene]

Note that this needs a rework of the logic on how the "latest package" is determined. I'll go the route of nuget and only using "stable" package versions (without suffix) for that, only serving packages with a suffix on explicit requests.