CBG-4289 fix import CV value for HLV code

[torcolvin]

Created new tests to cover import cases https://docs.google.com/document/d/19mC9-TptN7ynuF5XR9TQ_MckHWsSrjUfI2p71G_DD1U/edit#heading=h.xzdilbaiwy25

The specific bugs initially noticed were around _vv.ver getting updated to newVVEntry.Value = expandMacroCASValueUint64 which was never correct on import. Additional logic was expanded to cover all tests.

For ease of reading this code, the existing tests were ported to a parameterized test first with the buggy logic in place, you can read the commit separately.

Code is also tested with live XDCR.

Also removes ImportCAS as part of CBG-4285.

Pre-review checklist

• [x] Removed debug logging (fmt.Print, log.Print, ...)
• [x] Logging sensitive data? Make sure it's tagged (e.g. base.UD(docID), base.MD(dbName))
• [x] Updated relevant information in the API specifications (such as endpoint descriptions, schemas, ...) in docs/api

Integration Tests

• [ ] GSI=true,xattrs=true https://jenkins.sgwdev.com/job/SyncGateway-Integration/2746/