Ogmios; change tracking to connection time

Tasks:

Proxy:
1 - Create new metric called: `ogmios_proxy_total_connections`, to deprecate the old `ogmios_proxy_ws_connection`
(This is due to the fact that the old metric has weird data, and it's not possible to reset it)

Operator:
2 - Update operator to use this new metric for tracking usage
3 - Track usage based on open connection time, rather than packages. (replicate Node Operator)