Add rollback command to deployer

[amarthadan]

Close #1406

At this point src/infrastructure/index.ts should be refactored a bit, some common code can be extracted into functions and the whole thing should be divided into separate files. I'm leaving that for a separate issue.

[Siegrift]

I tested on AWS, looks good, but found a few edge cases which I think should not be present.

1. I can rollback even to current version
2. As a user I'd (or better said I could) expect the rollback to move the string "(current)" in the info output to the rollbacked version. However, what we do is we create a new version with config+secrets from the version to rollback to. I think this could be clarified in the output. E.g. Creating a new version <version_id> with configuration files from version <version_to_rollback>

[Siegrift]

Nit: Can we enforce it with eslint? I prefer the member import syntax, but I am OK with this if it's for the consistency sake.

[amarthadan]

I wasn't able to mock the functions from the fs module without it.

[amarthadan]

I can rollback even to current version

The thing is that if you don't change your config or secrets and deploy you're doing that anyway. So, it's a bit weird preventing it in one place but allowing it in another. But I get that rollback evocates something in the past. Ok, I'll add a check to prevent rollbacking into a current version.

As a user I'd (or better said I could) expect the rollback to move the string "(current)" in the info output to the rollbacked version. However, what we do is we create a new version with config+secrets from the version to rollback to. I think this could be clarified in the output. E.g. Creating a new version <version_id> with configuration files from version <version_to_rollback>

I agree, I'll do that.

[Siegrift]

👍 LGTM