Adding support for disabling default metrics using Tyk Chart

Hi Asha,

Sorry for the delayed response. I did try disabling the base metrics but the metrics are still exposed.

Below is my configuration

    - name: TYK_PMP_PUMPS_PROMETHEUS_META_DISABLEDMETRICS
      value: '["tyk_latency", "tyk_http_status", "tyk_http_status_per_path", "tyk_http_status_per_key", "tyk_http_status_per_oauth_client"]'

Sincerely,
Kaushal