Add Deployment annotations to helm chart

[maximpashuk]

Related to #183 , ability to add custom annotations to almost any k8s resource is important.

For exmple, I want to use keel annotations on deployment for portainer auto-update sceenario.
I cah workaround this by helmfile strategicMergePatches but this is kind of hack i think, native support would be nicer of cource.

[maximpashuk]

@jamescarppe pls take a look my feature request is not firstone