RSVP extra info

[NovaFox161]

Is your feature request related to a problem? Please describe.
Allow adding an extra field to RSVPs to show a role or additional "note" that a person has about their attendance.

Example use case would be for an MMO raid where you would include your role (like header, tank, etc)

Describe the solution you'd like
Add some way of adding info or a note to your rsvp, most likely extra command arguments instead of a whole new command, show it in parenthesis next to the user's name.

Example Command: !rsvp ontime divq9ihqhoq9hbm2tncj8set04_20171008T030000Z Main Healer

Example Output:

DisCal
RSVPs for Event
Event ID
divq9ihqhoq9hbm2tncj8set04_20171008T030000Z
On Time
Callador Julaan [Main Healer],
Late
N/a
Unsure
N/a
Not Going
N/a
`!event view <ID>` for event info

Describe alternatives you've considered
N/a

Additional context
N/a

[NovaFox161]

removed role from issue title since actual roles can now be assigned #78 on RSVP and could confuse people if using the same term even though it is your "role" in the event that is an example here.

I think it would still be nice to get this feature in, just not sure how we can do so and make it practical.