sap_ha_pacemaker_cluster: ANGI on RHEL and small improvements

[ja9fuchs]

Description

1. "ANGI" now also works on RHEL

   • RHEL pre-steps discover the package but will not resolve the package conflict if the classic agents are installed. A failure message explains the issue and the user has to solve it. This will prevent an unintended change of the entire setup if run against pre-configured nodes.
   • Adjustment of the VIP order constraint task to work with classic and 'angi'.

2. Adjustment of hook vars logic

   • Explicitly define hook preferences for _tkover and _chksrv vars in OS defaults.
   • The hook task now respects the hook control variable and the argument now works for user choices, overriding the OS preference.
   • The presence of the hook definition in the OS vars does not enforce the hook config anymore. This enables the definition of optional hooks.
   • In RHEL the _chksrv hook is also available and supported. The hook is optional, for customers to enable on demand.

3. A few cosmetical improvements of task names

4. Suspected typo fixed for __sap_ha_pacemaker_cluster_hanacontroller_resource_clone_name

   • I could not find a reference to mst_ and the argument default info also refers to cln_ as the prefix.

Tested

• ... on RHEL 9.4 in AWS for SAP HANA HA with 'classic' and 'angi' resource agents.
• Verified the hook enable choice to configure the hook that is not enabled by default on RHEL.

[marcelmamula]

LGTM with mst/cln changes