Enhancement: Remove unnecessary variable requirements for read-scale clusters

Reason: Read-scale clusters do not require creating users for Pacemaker and installing the `mssql-server-ha` package.

Result: This remove a requirement for unnecessary variables when running a read-scale cluster and requirement to install the `mssql-server-ha`, which depends on packages from HA repository.

Please provide the package NVR for which bug is seen:

ansible-collection-microsoft-sql-2.0.1-1.el8

How reproducible: Always

Steps to reproduce

• hosts: all
  vars:
  mssql_accept_microsoft_odbc_driver_17_for_sql_server_eula: true
  mssql_accept_microsoft_cli_utilities_for_sql_server_eula: true
  mssql_accept_microsoft_sql_server_standard_eula: true
  mssql_version: 2022
  mssql_password: "LS1setup!"
  mssql_edition: Developer
  mssql_manage_firewall: true
  mssql_ha_configure: true
  mssql_ha_ag_cluster_type: external
  mssql_ha_endpoint_port: 5022
  mssql_ha_cert_name: ExampleCert
  mssql_ha_master_key_password: "p@55w0rD1"
  mssql_ha_private_key_password: "p@55w0rD1"
  mssql_ha_reset_cert: false
  mssql_ha_endpoint_name: Mirroring_Endpoint
  mssql_ha_ag_name: AG1
  roles:
    - microsoft.sql.server

Expected results

The role finishes without trying to install mssql-server-ha

Actual results

TASK [microsoft.sql.server : Ensure the package mssql-server-ha] *********************************************************************************************************************************************

skipping: [rhel2test]

skipping: [rhelqs]

fatal: [rhel1test]: FAILED! => {"changed": false, "failures": [], "msg": "Depsolve Error occured: \n Problem: cannot install the best candidate for the job\n  - nothing provides resource-agents needed by mssql-server-ha-16.0.4065.3-4.x86_64", "rc": 1, "results": []}