sap_ha_pacemaker_cluster: GCP haproxy handling and new platform VIP dictionary

[marcelmamula]

Changes

1. GCP Preconfigure task was moved to block to execute only if proper gcp_nlb_reserved_ip_haproxy method is used. This is not necessary for ipaddr method.
2. New __sap_ha_pacemaker_cluster_sap_extra_packages_dict dictionary in OS var files to accommodate override over default VIP method. This is similar dictionary implementation as done before for stonith, extra packages and others.

Reason

haproxy is not documented method to be used on SUSE as per documentation from Google.

# SUSE - VIP: IPaddr2, Healthcheck: No pacemaker resources, but directly as part of NLB healthcheck
#   HANA: https://cloud.google.com/solutions/sap/docs/sap-hana-ha-config-sles#create_a_local_cluster_ip_resource_for_the_vip_address
#   NWAS: https://cloud.google.com/solutions/sap/docs/netweaver-ha-config-sles#create_the_vip_resources
# RHEL - VIP: IPaddr2, Healthcheck: haproxy
#   HANA: https://cloud.google.com/solutions/sap/docs/sap-hana-ha-config-rhel#create_a_virtual_ip_address_resource
#   NWAS: https://cloud.google.com/solutions/sap/docs/netweaver-ha-config-rhel#create_a_virtual_ip_address_resource

[ja9fuchs]

lgtm, adds flexibility to the VIP methods per platform and OS