Fix arguments of rate and history commands

[TimJentzsch]

Relevant issue: None

Description:

This fixes an error when executing the history and rate commands, because of an argument name mismatch.

Those were changed on the Discord side at some point, but not adjusted in the code. Additionally, a deprecated Pandas command has been changed.

Notably the legend for multiple users seems to be bugged, showing a dot in the first color for the second user. I have no idea why and will move this to a different issue:

Checklist:

• [ ] Code Quality
• [x] Pep-8
• [ ] Tests (if applicable)
• [x] Success Criteria Met
• [ ] Inline Documentation
• [ ] Wiki Documentation (if applicable)