Expose original unmodified version string through read-only property

[xavierdecoster]

Fixes NuGet/Home#5068

[emgarten]

I'm fine with this change, but I am not sure this should ever be used over ToString(). If this is for the gallery we should normalize all SemVer 2.0.0 versions to avoid the confusion non-normalized versions cause.

[joelverhagen]

If this is for the gallery we should normalize all SemVer 2.0.0 versions to avoid the confusion non-normalized versions cause.

We already have this behavior in the V2 feed. The Version property has always had the original version string. The NormalizedVersion has the normalized version plus any build metadata.

We improved this naming in V3. Version has the normalized version plus build metadata and VerbatimVerrsion has the original version string.

[joelverhagen]

Nit: could be public string OriginalVersion => _originalString right? I like that syntax 😄

[xavierdecoster]

Done 4baa3cc

[emgarten]

In that case, why allow a SemVer2 package to be uploaded where the normalized and non-normalized versions are different?

I suppose the client should have thrown on these from the start and solving it here won't help. I just really want the normalized vs original issue to go away, it's painful.