* Update fsm.go

* Update fsm.go

Simple addition to make this internal variable accessible (without relying on `stats` object, which is a brittle approach).

_Term_ is a fundamental concept in Raft consensus, so making it easily available to clients of this library seems like an obvious thing to do. There are also specific use cases supported by knowing the Term:

- Allow clients of this library to retrieve and display diagnostic information about the state of the Raft system.
- Support certain types of reads of a Raft-managed store. For example, if a client can check before and after a Read that an election has not taken place during the read, it allows those clients to make certain guarantees about the data read from the Raft-managed Store. One way to do this is to simply check that the Term has not changed (see [this discussion](https://groups.google.com/g/raft-dev/c/4QlyV0aptEQ/m/1JxcmSgRAwAJ) for more details).

Fix typos in docs, comments, and tests

Add CODEOWNERS file in .github/CODEOWNERS

Currently we have some legacy metrics with `peer_id` in the metrics suffix (in
addition to same metrics with `peer_id`d as label)
1. `raft_replication_appendEntries_rpc_peer0`
2. `raft_replication_appendEntries_logs_peer0`
3. `raft_replication_heartbeat_peer0`
4. `raft_replication_installSnapshot_peer0`

These metrics may have additional `_count` or `_sum` metrics. And each metrics
are multiplicative. Meaning if I have 10 peers, these metrics will be 10x.

This PR adds a flag `noLegacyTelemetry` (default: false) which by setting to
`true` you can skip those duplicate metrics.

---------

Signed-off-by: Kaviraj <kavirajkanagaraj@gmail.com>
Co-authored-by: Piotr Kazmierczak <470696+pkazmierczak@users.noreply.github.com>

* Introduce hashicorp/go-metrics compatibility

Compatability is attained with build tags

Using tag armonmetrics or no tag at all will result in the library utilizing github.com/armon/go-metrics for metrics emission (like the library historically has done)

Using tag hashicorpmetrics will result in the library utilizing the updated github.com/hashicorp/go-metrics for metrics emission.

…y instead of through the compat package (#633)

* Add a log line on active node when sending snapshot to a follower

* Add snap ID and peer ID to relevant log lines in sendLatestSnapshot; fix - use peer.ID instead of peer as a value in log line

* Add an INFO log line when opening a snapshot in sendLatestSnapshot