sap_ha_pacemaker_cluster: Add support for clustered WebDisp systems

[rob0d]

Hi all,
@marcelmamula @ja9fuchs
This PR adds option to configure a clustered SAP Web Dispatcher system.

Rationale: SAP WebDisp (WD) needs to be resilient in the same way Central Services (ASCS) do.
In cloud environments resiliency is generally achieved by installing multiple WD instances and putting a load balancer in front of them. However, with on-prem deployments load balancer is usually an overkill for small to medium deployments as it can have impact on supportability and costs. So specifically with on-prem bare-metal and VMware installations in mind this PR adds supports for clustered WDs.

Thanks to the clever way the ha_pacemaker_cluster role is written, it was relatively easy to add another host type (sap_ha_pacemaker_cluster_host_type): sap_webdisp to achieve it.
As far as I can tell (tested on 8 systems) it is completely non-impacting enhancement and can be used stand-alone or together with other cluster host types (mainly nwas_abap_ascs_ers).

It was tested on-prem only and may need a minimal enhancement for different cloud providers. Although I am not sure if there is a usage case for that.

The minimal input for it to work is as the following:

# SID and Instance Numbers for WebDisp.
sap_ha_pacemaker_cluster_wdp_sid: <WebDisp SID>
sap_ha_pacemaker_cluster_wdp_instance_nr:  <xx>
 
# Profile name created by the installer
sap_ha_pacemaker_cluster_wdp_sapinstance_instance_name: "{{ sap_ha_pacemaker_cluster_wdp_sid }}_W{{ sap_ha_pacemaker_cluster_wdp_instance_nr }}_<virtual_wdp_hostname>"
sap_ha_pacemaker_cluster_wdp_sapinstance_start_profile_string: "/sapmnt/{{ sap_ha_pacemaker_cluster_wdp_sid  }}/profile/{{ sap_ha_pacemaker_cluster_wdp_sid }}_W{{ sap_ha_pacemaker_cluster_wdp_instance_nr }}_<virtual_wdp_hostname>"
sap_ha_pacemaker_cluster_vip_wdp_ip_address: <virtual_wdp_ip>
 
# Filesystem definitions for WebDisp
# the rest can remain default
sap_ha_pacemaker_cluster_wdp_filesystem_host_mount_path: "{{ sap_storage_setup_nfs_local }}/usr/sap/{{ sap_ha_pacemaker_cluster_wdp_sid }}/W{{ sap_ha_pacemaker_cluster_wdp_instance_nr }}"

Note: For some reason Github has decided that few files can't be merged automatically and is marking the whole file as different even though only 1 line was changed. I'm not sure if I've done something wrong, but I can't see it. Any advice would be appreciated.