[ci] Simplify ci monitoring with custom actions

[marun]

Previously, enabling monitoring of temporary networks for a CI job required duplicating complicated action steps. Encapsulating those steps in a custom action is intended to simplify maintenance and enable direct reuse by other repos (e.g. subnet-evm, hypersdk).

TODO

• Verify metrics collection
• Merge [ci] Add actionlint job #3160

[tsachiherman]

looks good. Note that if you get to the point where you'd be using the same action across multiple github repositories, you could create a "common" repository that would host these shared actions.
That's particulary useful when you have a username/password that is stored as part of the repository secrets, and you want to make sure there is only a single "instance" of it.

[marun]

looks good. Note that if you get to the point where you'd be using the same action across multiple github repositories, you could create a "common" repository that would host these shared actions. That's particulary useful when you have a username/password that is stored as part of the repository secrets, and you want to make sure there is only a single "instance" of it.

It won't actually be necessary to put these actions in a different repo to enable reuse. That's already possible from this repo. I intend to update subnet-evm and hypersdk to use the new actions defined in this PR.

But custom actions don't enable sharing of secrets, as per the example of each invocation of the monitoring action in this PR needing to provide the monitoring secrets. Custom actions are a bit strange in their access to the environment - context values are accessible via input defaults but not directly in steps, and secrets are not accessible at all and need to be provided via inputs.