Telemetry Poller default VM metrics

[janciesla8818]

This PR adds metrics that are gathered by default by Telemetry Poller. Following metrics are updated:

• vm_memory_total - Total amount of currently allocated memory.
• vm_memory_processes - Amount of memory currently allocated for processes.
• vm_memory_processes_used - Amount of memory currently used for processes.
• vm_memory_binary - Amount of memory currently allocated for binaries.
• vm_memory_ets - Amount of memory currently allocated for ETS tables.
• vm_total_run_queue_lengths_total - A sum of all current run queue lengths.
• vm_total_run_queue_lengths_cpu - A sum of current CPU schedulers' run queue lengths.
• vm_system_counts_process_count - Number of process currently existing at the local node.

Following metrics are moved from Count to Gauge section:

• sparrow_pools_warden_pools_gauge - The current value of the selected measurement from the most recent event.
• sparrow_pools_warden_workers_gauge{pool=${POOL}} - Current number of workers operated by a given worker POOL.

Metrics collection was tested manually together with checking if they are correctly displayed correctly in grafana.

[michalwski]

Nitpicking: the fixes to documentation could be done in a separete PR :)