Hindsight input/analysis log file pruner

Deletes the log files generated by the input and/or analysis plugins when all the analysis and output plugins are done consumining them (within ticker_interval seconds).

1. Sample Configuration

filename = "prune_input.lua"
ticker_interval = 60
input = true
analysis = true

-- When true, causes the plugin to stop/abort when the checkpoints are no longer
-- advancing. Use this option to allow hindsight_cli to exit when the inputs are
-- finished. This option is typically used when streaming a large data set from
-- something like s3 i.e., running a report.
exit_on_stall = false

source code: prune_input.lua