Previously block processing would log a single statement like this:

<timestamp> Channel [myc]: Committed block [16] with 1 transaction(s)

To receive any more information, operators would have to turn
on debug, which provides an overwhelming amount of information.

A middle ground is needed, where operators receive the most
important block processing information (high level steps and timings)
to help them understand peer health and bottlenecks,
but without the overwhelming amount of debug noise.

This change improves the INFO logging per block as follows:

<timestamp> [myc] Received block [57] from buffer
<timestamp> [myc] Validated block [57] in 5ms
<timestamp> [myc] Committed block [57] with 1 transaction(s) in 24ms
                  (state_validation=7ms block_commit=0ms state_commit=16ms)

This change also:
- improves core.yaml defaults to pick up some important gossip INFO
statements (without adding noise)
- standardizes on the log statement prefix of [channel_name]
- starts to roll the [channel_name] prefix down to debug statements
  (a full sweep can be done in a next release)
- standardizes timings to utilize ms (milliseconds)

Change-Id: I97f3b307a167ce8f445f3cc625bad3b2282b026d
Signed-off-by: David Enyeart <enyeart@us.ibm.com>
Signed-off-by: yacovm <yacovm@il.ibm.com>
Signed-off-by: manish <manish.sethi@gmail.com>