[Feature Request] Ability to Change About Information

**Is your feature request related to a problem? Please describe.**
When running the about command, the bot currently gives a preset answer that I do not believe can be changed.

**Describe the solution you'd like**
It'd be cool if there was a config option to be able to change the text in the about box

**Describe the basic flow/steps of using this feature**
How this feature would be used:
1. Open up config.txt
2. Go to the setting for the about command, which has a json formatted discord embed or the likes
3. Edit the embed

**Additional context**
N/A

**Please check the following links to confirm that your feature has not already been requested:**
https://github.com/jagrosh/MusicBot/labels/enhancement
https://github.com/jagrosh/MusicBot/wiki/Things-That-Won%27t-Be-Added

Start by locating the implementation of the about command and the config.txt settings described in the issue. Determine how the about response is currently defined and what configuration format it supports; done would mean users can edit the about embed or text through config.txt.

Written by the indexing model from the issue text.