Add remote_write.queue_config.sample_age_limit definition to prometheus configuration

[pizycki-allegro]

Adds recently added configuration for Prometheus remote_write https://prometheus.io/docs/prometheus/latest/configuration/configuration/#remote_write

# Configures the queue used to write to remote storage.
queue_config:
  ...
  # If set, any sample that is older than sample_age_limit
  # will not be sent to the remote storage. The default value is 0s,
  # which means that all samples are sent.
  [ sample_age_limit: <duration> | default = 0s ]

[github-actions[bot]]

Thanks for the PR!

This section of the codebase is owned by @madskristensen and @hyperupcall - if they write a comment saying "LGTM" then it will be merged.

[madskristensen]

Thanks