feat: Allow suppressing annotations and labels

[antoinedeschenes]

Allows suppressing annotations and labels in the diff output.

Fixes #390.

Useful to ignore changes that might not make an helm upgrade worthwhile, such as chart version labels. Also allows hiding labels containing sensitive information, such as kubectl.kubernetes.io/last-applied-configuration on secrets when using three-way-merge.

It currently doesn't handle pod templates in deployments, etc. which could still be very useful (to hide checksum annotation changes, for example).

[yxxhero]

@antoinedeschenes any updates?

[yxxhero]

https://github.com/databus23/helm-diff/pull/475