XDCR - Connection Pre-check doesn't support all inputs that XDCR normally would accept

Connection pre-check as of now will use the hostname field in remoteRef to get the target nodes' info from target cluster. The feature has the following limitations, in contrast to how XDCR remote reference creation would do it:

1. If the input for remote ref creation is a DNS SRV, XDCR remote ref creation will treat it automatically differently as it needs to resolve to A records before proceeding to connect. Connection pre-check doesn't give this special treatment for DNS SRV. It directly uses the input hostname to connect to the target.
2. XDCR remote ref creation is also intelligent enough to auto-check if the intent of the user is to use alternate address and alternate ports, if such configuration is setup for the target cluster. Connection pre-check on the other hand always deals with non-alternate target cluster node addresses to perform connection checks.
3. XDCR remote ref creation also does a auto check to either use secure or non-secure mgmt port (8091 or 18091) irrespective of user input (or even if no port is provided or alternate ports are provided) . Connection pre-check for secure connection needs 18091 (or secure mgmt port) as input.