Improved global rate limiting metric keys

Description: Currently global rate limit keys look like the following envoy-gateway-system/gateway/rule/0_gateway/gateway/rule/0

it would be nice if we could have a easier way to identify which rule this is as position 0 in array is not very useful. This also means dashboards/alerts that use this key may break if the ordering changes.

I suggest we introduce maybe a name key? So we at least can add this to the end for example

envoy-gateway-system/gateway/rule/0_gateway/gateway/rule/0/basic-limit