Proposal: separate format version from library/http version

Right now versioning is not very clear in Noms. It was created before Go modules existed, so it's not entirely our fault, but anyway.

I have mod-ularlized Noms awhile ago, so we should also adopt Go's versioning convention. Namely, the Noms git repo should be tagged using semver.

Currently, we have the following git tags:

!? git tag -l
last-js
latest
v7
v7.3
v7.4

v7 contained the snapshot of the last version of the Noms format before we started changing it in preparation for a major new version 8. v7.3 and v7.4 are incremental updates on the way to 8. Currently the code says: const NomsVersion = "7.18", so I guess we stopped tagging the repo at some point.

In any case, I no longer have any plans to do a major new version of the format rolling up a bunch of changes so I think we can just call 7.18 the current stable format version and be done with that.

That still leaves the library version. I think that we should version the library according to Go conventions and version the data format separately.

Concrete proposal

• Tag the current Noms head v10.0.0 and make that the current Go library version. This makes it clearly different than the "format" version which is 7.18.
• Modify noms version and so-on to report both the format version and the library version.