refactor: client => dapi

[coolaj86]

"client" is too generic - sounds like it could refer to a http or tcp client, however, this is highly specific to the platform, so it makes sense to call this dapi as to not be confused with other clients that may exist in the code and be more clear to the reader

sd 'client' 'dapi' *.js */*.js

[markin-io]

DAPI is the HTTP/GRPC interface in front of the Core and Platform.
SDK is a client to DAPI, and SDK could work in offline mode without connection to DAPI (e.g. to just create and sign transactions).

Having this in mind, renaming client to dapi and clientOptions to dapiOptions won't be correct.

[coolaj86]

SDK could work in offline mode without connection to DAPI

Well, as long as we're agreed that that makes client an even worse name.

Could call it dash, or dp?

I still think dapi is just fine as it is the representation of the application programming interface - which includes offline functions - not a representation of the wire protocol.