Couchbase-cli: add XDCR replication prioritization

Need CLI support for replication prioritization feature for XDCR (MB-31172).

Replication level setting :

1. Assigning priority
   This feature provides users the ability to assign priorities at the replication level with three modes: High, Medium, Low. - So, a user should be able to set this at the replication level using the CLI. So, when a user adds a new replication, they can use one of these parameters. High is the default.
2. Desired Latency (Setting threshold for backlog)
   Desired Latency is the ratio of the No. of mutations left to process/ No. of mutations that can be processed in a second (throughput). We want customers to specify what is their desired number for the latency.
   basically, they can plug in the number for latency as "10s". In that case, let's say 20K (mutations left to process)/1000 (total num of mutations that can be processed in a second), then it will take 20s to complete replication and accept any new mutations. The 10s will not be met, so XDCR resource management will kick in to try if resources can be obtained from lower priority mutations.
   The CLI should be provided where the customer can plug in the value for this in ms.

Cluster level setting :

1. As the new replications are added, it will require more resources to maintain the replication throughput. We want to provide users an option to allocate more resources to XDCR. (Go max procs). <I believe REST API for this already exists>. We need CLI to allocate more resources to XDCR, if the customer desires to maintain good efficiency.