Feature: `/whitelist` with minutes and seconds for 1.16, 1.15 and 1.7 bots

[its-saanvi]

Problem

Whitelisting players for splits is currently only supported in minutes which is very restrictive. Having it work for minutes:seconds would be a nice addition.

Solution

Allow whitelisting players for all splits in minutes as well as seconds.

References

A similar thing has been done with the AA bot with hours:minutes:

1. Whitelist command.
2. Parsing and storing.