Adding a annotation flag to trigger rollout on change of cm/secrets

[wololowarrior]

Fixes #773

#724 This pr removed the functionality of triggering a rollout strategy on change of configmap/secrets.
But there are some cases when we want to trigger a rollout instead of just restarting the pod.

As part of this pr,

1. Adding a new annotation reloader.stakater.com/triggerRollout if set to true will trigger a rollout strategy for that rollout. The default can be unset or false, so current behaviour should continue on.

Example
Setting as true

apiVersion: argoproj.io/v1alpha1
kind: Rollout
metadata:
  name: simple-rollout
  annotations:
    reloader.stakater.com/auto: "true"
    reloader.stakater.com/triggerRollout: "true"
spec:
  replicas: 2

[wololowarrior]

@MuneebAijaz Can i get some maintainers reviews?

[wololowarrior]

@MuneebAijaz @karl-johan-grahn Would appreciate 👀 and reviews on this whenever possible!

[karl-johan-grahn]

@wololowarrior can you please add a unit test for this? You can take inspiration from existing tests

[wololowarrior]

@karl-johan-grahn Added a test for rollout. Weirdly there weren't any tests for it so more code than usual.
I've added a test for one part of the branch. Which had the old behaviour of triggering a rollout strategy.

I also tried writing a test for the case where its a rolling update, but that test doesn't seem to pass. I suspect this is because the stubbed rollout client isnt built to handle restartAt cases.

[karl-johan-grahn]

Cross-referencing #817 that addresses the same issue #724

[wololowarrior]

@karl-johan-grahn fixed ci.
Which pr do you guys prefer?