[Feature Request] Add remove range command

**Is your feature request related to a problem? Please describe.**
N/A

**Describe the solution you'd like**
I would like a command that allows the user to remove a range of songs in the queue. The main difference between this feature and the skip command is that this feature would allow the user to set/format the queue and just forget about it, unlike the skip command where it has to be done each time a song ends.

**Describe the basic flow/steps of using this feature**
How this feature would be used:
1. Queue a number of songs (like a playlist)
2. Use a command such as `-removerange [start] [end]`
3. Examples: `-removerange 2 5`, `-remove range 2 5`, `-remove 2-5`, `-rr 2 5`

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

The issue names the existing skip command, queue behavior, and proposed command forms, but no files or tests. Start by locating the skip command and queue handling, then define the range semantics and confirm that a command such as `-removerange 2 5` removes the selected songs without repeated skips.

Written by the indexing model from the issue text.