Expose /pressure also in Prometheus Metrics

[wodka]

Is your feature request related to a problem? Please describe.
Currently browserless internal metrics are only exposed on /pressure. It would be great to include them in /prometheus

Describe the solution you'd like
expose browserless metrics like:

// http://localhost:3400/pressure
{
  "pressure": {
    "date": 1665761298012,
    "reason": "",
    "message": "",
    "isAvailable": true,
    "queued": 0,
    "recentlyRejected": 0,
    "running": 1,
    "maxConcurrent": 10,
    "maxQueued": 10,
    "cpu": 5,
    "memory": 63
  }
}

goal would be to get metrics like:

• browserless_queued
• browserless_recently_rejected
• browserless_running
• browserless_max_concurrent
• browserless_max_queued
• browserless_cpu
• browserless_memory

#381 was a nice start but only exposed the node metrics.

[joelgriffith]

These should all be in /pressure now -- please reopen if no the case

[Asgoret]

@joelgriffith can we reopen this issue or create another? Pressure contains necessary data about queue

[omri-shilton]

We would also like to have pressure in prometheus mode @joelgriffith
@wodka can you reopen this?