Standardize metric counter names

[ScottMansfield]

There's a lot of metrics like cmd_replace_not_stored_l2 that are somewhat vague in what they represent. It could have been a replace in service of a set or an add. In the L1L2Batch orca there are metrics that specify what larger operation the sub-operation is in service of. This pattern should be applied across the board to make the metrics more manageable organizationally. There will be a lot of metric name changes, but luckily we aren't tracking specific metrics in an automated fashion yet. I think keeping counts for all replace commands sent to L2 would be useful, as it can be correlated with what the L2 storage says. Each operation in the separate orcas ought to have some way of differentiating themselves, though it might be a metric explosion at that point. Needs some more thought.

[ScottMansfield]

At this point the metrics are fairly well ingrained so this is not really needed. Closing.