Disable grub timeout in SLES for SAP 16.0 tests on pvm_hmc

The default 8s timeout can cause some tests on pvm_hmc backend
to fail as `lib/sles4sap::reboot()` would call 2 times
`lib/opensusebasetests::wait_grub()`, and 8s could be not enough time to
assert the grub screen twice.

This commit disables the grub timeout on SLES for SAP 16.0 installations
by adding `stopOnBootMenu: true` in
`data/sles4sap/agama/sles_sap_default_ppc64le.jsonnet` and also adds in
the related schedules the module `installation/grub_test` to handle the
grub screen before first boot.

Related Ticket: https://jira.suse.com/browse/TEAM-10611

Author: alvarocarvajald

data/sles4sap/agama/sles_sap_default_ppc64le.jsonnet

@@ -3,6 +3,9 @@
     id: '{{AGAMA_PRODUCT_ID}}',
     registrationCode: '{{SCC_REGCODE_SLES4SAP}}',
   },
+  bootloader: {
+    stopOnBootMenu: true
+  },
   root: {
     password: '$6$vYbbuJ9WMriFxGHY$gQ7shLw9ZBsRcPgo6/8KmfDvQ/lCqxW8/WnMoLCoWGdHO6Touush1nhegYfdBbXRpsQuy/FTZZeg7gQL50IbA/',
     hashedPassword: true,

schedule/sles4sap/agama_saptune_on_pvm.yaml

@@ -12,6 +12,7 @@ vars:
 schedule:
   - installation/bootloader
   - installation/agama_reboot
+  - installation/grub_test
   - installation/first_boot
   - console/system_prepare
   - sles4sap/saptune/mr_test

schedule/sles4sap/hana/pvm_hana_cluster_node_sle16.yaml

@@ -40,6 +40,7 @@ schedule:
   - '{{barrier_init}}'
   - installation/bootloader
   - installation/agama_reboot
+  - installation/grub_test
   - installation/first_boot
   - ha/wait_barriers
   - console/system_prepare

schedule/sles4sap/sles4sap_agama_auto_install_pvm_test.yaml

@@ -7,6 +7,7 @@ schedule:
   - '{{barrier_init}}'
   - yam/agama/boot_agama
   - installation/agama_reboot
+  - installation/grub_test
   - installation/first_boot
   - console/system_prepare
   - console/consoletest_setup