Document for installing CBL Vector Search XCFramework using Carthage

In CBL 3.2.0 / Vector Search 1.0.0 GA, we will need to update the instruction for installing Vector Search for iOS / macOS to include the Carthage instruction.

The info is the same as what is decribed in this link for Carthage:
https://docs.couchbase.com/couchbase-lite/current/swift/gs-install.html

We will have a new URL for vector search carthage binaries.