Subscription triggers and their outcomes should be visible in BarViz

[premun]

Context

When people trigger subscriptions, there's no feedback loop of how the trigger went:

• There might be no new update.
• There might be a service error that prevented the service to open a PR.
• There might already be an existing PR and/or it can have a PR with running checks which prevent the service to flow the new update there.
• There might be a user error (e.g. invalid Version.Details.xml) which prevent the service to open the PR.
• ...

Goal

Store the outcome of the last trigger of every subscription somewhere (Redis?) and then display it in BarViz so that people can check what is the state.