Polls rework

[EasyXploit]

Redo the survey system, to use a menu with buttons to add, modify or delete fields/options, add a general description and adjust whether multiple or individual selections are allowed, among others.

Also replace the interval remaining time update with a formatted Unix timestamp.

Show the votes count in an anonymous way.

Reward the polls filling with credits.

Wait for new field types for modals?

Use the Canvas module to display a graph with the current progress of ongoing surveys, and the results of completed surveys.

https://www.youtube.com/watch?v=TT1InsXUHTo

https://code.tutsplus.com/tutorials/how-to-draw-a-pie-chart-and-doughnut-chart-using-javascript-and-html5-canvas--cms-27197

[EasyXploit]

This feature will be removed in favour of the integrated one: https://support.discord.com/hc/en-us/articles/22163184112407-Polls-FAQ