[appmesh-prometheus] Support for PODs annotations

We've enabled appmesh-prometheus in our clusters, however they can't downscale given this application prevents autoscaler to downsize due to appmesh-prometheus local storage.

It is easily avoidable by adding an annotation to pods, however appmesh-prometheus doesn't support annotations.

Start by locating the appmesh-prometheus chart and its pod template or values entry points. Check how pod configuration is currently exposed, then add support for configuring pod annotations and verify that the rendered manifests contain them when set.

Written by the indexing model from the issue text.