ROSA should be able to request a single instance

[cooktheryan]

Name of Feature or Improvement

When using ROSA and a multi-AZ environment currently 3 instances are requested (1 per AZ). Configuration exists within the ROSA cli to launch just a single instance.

Description of Problem the Feature Should Solve

Right now we are scaling unnecessary resources.

Describe the Solution You Would Like to See

May just need to update the OCM libraries to support the functionality.

Describe Alternatives You Have Considered

Tekton tasks could be hacked together to use the ROSA cli to do this.

Additional Context

err

Error creating MachinePool: status is 400, identifier is '400', code is 'CLUSTERS-MGMT-400' and operation identifier is 'dac7c9af-17a8-46d5-83fa-d3c11092437d': Invalid number of replicas: 1. Multi AZ clusters require that the MachinePool replicas be a multiple of 3

ROSA CLI

rosa create machinepool --cluster=REDACTED --name=small --replicas=1 --availability-zone=us-east-2c