feat(upgrade-job): add support for loki-stack helm chart upgrade

[niladrih]

Requires #386.

Overview:

• adds new yq commands to delete objects, append to objects, and append to arrays.
• adds special upgrade values.yaml update for loki-stack changes from Update loki-stack and set health_check_targets: false. #386. Introduces migrations and set_literal_value updates to alter the existing yaml till it resembles the new one.
• replaces all &Path is the helm::yaml::yq module with AsRef<Path>.

Changes:

• removes .loki-stack.loki.config.ingester.lifecycler.ring.kvstore as it
  does not exist in loki-stack v2.9.11
• adds set value for the grafana/loki container image tag
• removes .loki-stack.promtail.config.snippets.extraClientConfigs as it
  does not exist in loki-stack v2.9.11
• removes .loki-stack.promtail.initContainer as it does not exist in loki-stack
  v2.9.11
• migrates .loki-stack.promtail.config.lokiAddress to .loki-stack.promtail.config.clients
• adds yq command_output helper function
• add set value for .loki-stack.promtail.readinessProbe.httpGet.path
• migrate .loki-stack.promtail.config.snippets.extraClientConfigs to
  .loki-stack.promtail.config.clients

[tiagolobocastro]

Replaces the loki and promtail yaml objects entirely to new defaults. Doesn't honour user's configuration for the older loki/promtail. This should be okay, as this is not a critical storage component (@tiagolobocastro wdyt?).

I don't think this is a good idea, enabled and persistence are in loki, we should not modify these.

[niladrih]

Replaces the loki and promtail yaml objects entirely to new defaults. Doesn't honour user's configuration for the older loki/promtail. This should be okay, as this is not a critical storage component (@tiagolobocastro wdyt?).

I don't think this is a good idea, enabled and persistence are in loki, we should not modify these.

The enabled is in loki-stack. This is preserved. There are 4 items under loki-stack: enabled, localpvScConfig, loki, promtail. The loki and promtail are overwritten. The other 2, are retained.

[niladrih]

I agree that persistence block items should be taken forward.

[niladrih]

This change now handles loki-stack helm chart update like it handles other changes to helm chart default values: it sets the new values to the final values manually.
This means all user configuration is carried forward.

[niladrih]

bors merge

[bors-openebs-mayastor]

🕐 Waiting for PR status (Github check) to be set, probably by CI. Bors will automatically try to run when all required PR statuses are set.

[bors-openebs-mayastor]

Build succeeded:

• continuous-integration/jenkins/branch