rename variables to reflect the metric name
fix comments for exported methods
explicitly record per schedule per schedule metric values
initialize metrics and change variable name to match with that of metric
add metric for recording failed volume snapshots
use singular variable instead of plural
remove extra field for failed snapshots, calculate using existing fields
initialize failure metric and rename methods
Signed-off-by: Shubheksha Jalan <jshubheksha@gmail.com>