[Feature] Rotate dataDirectory data

## Description
Currently, bitcoin-augur-reference stores to where `persistence:dataDirectory` is defined in the config.yml
However, as time passes, the machine will eventually run out of memory.

I am proposing we add an optional config value
`dataRetentionPeriod` or `storageDuration` or `dataTTL`

where, if it is not defined, default to the current behavior of unlimited; however, if defined, then delete any buckets past the retention period.

We can pass in as an `int` representing days

## Example
(30 days) `dataRetentionPeriod: 30`
(1 year) `dataRetentionPeriod: 365`

## Motivation
This would be useful where storage is a constraint. There are lots of full Bitcoin nodes that are running on 1 tb hard drives, and if they only need the last month of data, then holding onto anything past might be unnecessary.

Also, we should not be forcing users to clear out data manually

#### Note
I'm not sure how much time I have to work on this so if someone else want to pick it up feel free to do so. Otherwise, I might pick it up in the future