Polling and rules verification

[hauntii]

This PR adds the following to Bandwidth:

• Polling using canvas and selection menus
• Rule management and verification

Heads up: these have a lot of pictures.

About polling

Polls can be created with the command `/poll`. This will popup a modal with up to five total options! As soon as the modal is submitted a poll will be sent in the channel the command was sent in.    Polls can be set to have an expiry time from the command. This time is formatted as a unix timestamp.  Polls will end at their expiry time (if they have one), or can be closed immediately from the message's context menu.  When polls expire, users are no longer able to vote and the winner is highlighted with a shiny green!  Polls update every minute in order to stop ratelimiting from too many updates.

About rule management

Rules can be managed with `/rule` and its subcommands, `create, update, preview, remove`. Creating a rule is as simple as running `/rule create` and filling out the details! You can set a time users will have to wait during verification here. I recommend to increase it for more important rules. ( I use 5 as a standard )  You will then see a preview, and can choose to create the rule. It will be added to the end of the rule list.  If for some reason you have to update a rule, you can do that too! Using `/rule update` is just as easy as creating a rule. Just select the rule you want to edit, and you'll see the same process for creating a rule.  If you don't like a rule you've made, you can simply remove it with `/rule remove` and selecting the rule you don't want. If you want to see what a user sees during verification, just run `/rule preview` and select it. 

About rule verification

Once setup, users will be given an "unverified" role on join. (Setting `unverified_role_id`) If permissions are setup properly, users will have to use the `view-rules` button to have the role removed and full server access given. When the button is pressed, Bandwidth will reply with a rules onboarding where users will wait the time specified during rule creation to continue. If it is 0, they may instantly continue.   When they have reached the last rule, they will be presented with a `Verify` button that removes the role when the timer expires. `@everyone` should *not* have access to the verification channel. 

[jonbarrow]

Doesn't Discord already have this kind fo rules onboarding built in?

[hauntii]

The built-in onboarding is "click a checkbox and you're in", which isn't very effective. I know I've clicked straight past it multiple times (because usually I read the rules already) but most users dont read the rules, so this is just a more strict gate.

[jonbarrow]

Can't users still just click past all this too?

[hauntii]

In theory yes, but as there's an adjustable timer it's a bit more encouraging to actually read it.