Use recommended kubernetes labels

[mortenlj]

There is a set of recommended labels that overlap to some degree with the labels we set. Should we transition to using the recommended labels instead of (or in addition to) the ones we set?

https://kubernetes.io/docs/concepts/overview/working-with-objects/common-labels/

I think we at least could add these:

app.kubernetes.io/name: myapp
app.kubernetes.io/version: "5.7.21"
app.kubernetes.io/managed-by: fiaas

See also #9 for a related issue.

[oyvindio]

I think it makes sense to add these to the list of managed labels. I think for example the app label is convenient and would prefer to keep that in addition to rather than replace it with app.kubernetes.io/name