add setup snapshot to install packages into snapshot

[richm]

No description provided.

[richm]

The goal here is that we can create a snapshot of the VM image pre-loaded with packages that take a long time to install like kmod-kvdo, then use that snapshot for subsequent tests.
The code that creates and initializes the snapshot is here: https://github.com/linux-system-roles/tox-lsr/blob/main/src/tox_lsr/test_scripts/runqemu.py#L546-L597

The main thing this PR does is to allow test playbooks access to the inner variables of the role, e.g. the list of packages per-platform.

This is currently only enabled for the ansible 2.12 test runner (the rhel7 runner qemu guest crashes when trying to use the snapshot)

the test runner will need to be changed to use tests/setup-snapshot.yml

[nhosoi]

lgtm

A bit confused that these files are not related to the "snapshot"; just added because they were missing?
tests/tests_create_lvm_cache_then_remove_nvme_generated.yml
tests/tests_create_lvm_cache_then_remove_scsi_generated.yml
tests/tests_fatals_cache_volume_nvme_generated.yml
tests/tests_fatals_cache_volume_scsi_generated.yml

[richm]

lgtm

A bit confused that these files are not related to the "snapshot"; just added because they were missing?

yes - the nvme_generated and scsi_generated are supposed to be generated by the developer upon commit - I have a git post-commit hook that generates these so I don't forget . . .

tests/tests_create_lvm_cache_then_remove_nvme_generated.yml tests/tests_create_lvm_cache_then_remove_scsi_generated.yml tests/tests_fatals_cache_volume_nvme_generated.yml tests/tests_fatals_cache_volume_scsi_generated.yml

[vojtechtrefny]

lgtm
A bit confused that these files are not related to the "snapshot"; just added because they were missing?

yes - the nvme_generated and scsi_generated are supposed to be generated by the developer upon commit - I have a git post-commit hook that generates these so I don't forget . . .

My bad, that should have been part of #235. I have added a short paragraph about the generated tests to README-devel (#261) so I should remember it next time.

[spetrosi]

lgtm

[richm]

[citest]