add kubernetes metrics

[maksim-paskal]

add metrics for kubernetes API request, expose prometheus metrics, this metrics can help to observe kubernetes lags

aks_node_termination_handler_apiserver_request_duration_bucket
aks_node_termination_handler_apiserver_request_total

for this change, need refactor kubernetes client creation, move this funcs to client package

also extend metrics labels for

aks_node_termination_handler_error_reading_endpoint_total
aks_node_termination_handler_scheduled_events_total

add node and resoure labels, for better observability