query documents with n1ql from CLI or SDK

First comment:

• [ ] a n1ql example of querying documents in a given channel.
• [ ] java equivalent
• [ ] c# equivalent
• [ ] node.js equivalent
• [ ] go equivalent

Once this is documented, we should probably discuss about removing the `views` feature from the docs https://developer.couchbase.com/documentation/mobile/1.4/guides/sync-gateway/views/index.html (which is unsupported).

No n1ql visibility to XATTRs.

see other comments: https://github.com/couchbaselabs/couchbase-mobile-portal/issues/729