Add ability to customise pod annotations

[artemiyplotnikov]

Please add ability to customise pod annotations for deployment k8s-image-availability-exporter for example:

  template:
    metadata:
      {{- if .Values.k8sImageAvailabilityExporter.annotations }}
      annotations:
       {{- include .Values.k8sImageAvailabilityExporter.annotations . | nindent 8 }}