Enhancement: Allow user to define transaction time grouping in place of Month Start - Month End default behavior

[logan-life]

By default, transactions are ingested then processed and grouped by month.

In practice, the financial cycle of a given person may be between two dates: payday and the day before the next payday.

For people who do not get paid on the 1st of every month, it would be good to be able to customize the cycle length.

For example, if a person gets paid on the 23rd of each month, then it would be nice to have the transactions grouped into pay-cycles, so everything from the 23rd on Month One to the 22nd of Month 2.

For extra helpfulness, add a check to the cycle start day to see if it is a weekend day. If so, the cycle gets pushed earlier to the Friday before the payday. Similar bounds checking for the end of cycle day.