Feature(new_metrics): migrate replica-level metrics

[empiredan]

The replica-level entity can be bound to replica_base, since all of the classes (pegasus_server_impl, replica, etc., see classes in following sub-tasks) that hold replica-level metrics are derived from replica_base; Moreover, these classes also accept replica_base * as a parameter of their constructors.

Therefore, the replica entity can just be instantiated just in the constructor of replica_base; then, all of the classes that hold replica-level metrics will be instantiated with the replica entity from replica_base.

All classes (except pegasus_server_impl and replica) that hold replica-level metrics are a member of pegasus_server_impl, which is a member of replica and created at replica::init_app_and_prepare_list(), thus the lifetime of all replica-level metrics are bound to a replica: they will be released once a replica is deleted.

The replica-level metrics are distributed on following classes and source files. The migration for them can be divided into following tasks:

• [x] https://github.com/apache/incubator-pegasus/issues/1344
• [ ] https://github.com/apache/incubator-pegasus/issues/1336
• [x] https://github.com/apache/incubator-pegasus/issues/1333
• [ ] https://github.com/apache/incubator-pegasus/issues/1334
• [ ] https://github.com/apache/incubator-pegasus/issues/1342
• [ ] https://github.com/apache/incubator-pegasus/issues/1343
• [x] https://github.com/apache/incubator-pegasus/issues/1412