Create Telegram Poll handler

[jwflory]

Summary

Add a handler for Poll message objects sent from Telegram

Background

Is your feature request related to a problem? Please describe:

Telegram users can create interactive polls to send in groups. When a poll is created and sent, nothing is sent over to IRC.

Describe the solution you'd like:

A TeleIRC v2.x.x version should handle Telegram Polls. IRC users should receive the question text and option text. Obviously there is no way for IRC users to respond to a Telegram Poll.

Describe alternatives you've considered:

We could come up with logic for IRC users to respond to polls via the Telegram API by using /commands from IRC, but first let's get a basic handler implemented in the same way we are approaching Documents (#248).

Details

1. Telegram user creates and sends poll to group (e.g. "Tea or Coffee?" op1: "Tea" op2: "Coffee")
2. Three new messages are sent over to IRC: "@jwflory created a Telegram poll: Tea or Coffee?\n"Option 1: Tea"\n"Option 2: Coffee"

Outcome

Better user experience for IRC users when Telegram users create interactive content not compatible with IRC

[jwflory]

Discussed in 2020-04-11 meeting.

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@10eMyrT asked if this handler should be part of v2.0.0. We decided to not include it for v2.0.0 officially, but if circumstances arise where all other issues are in progress and someone is looking for something they do, they could work on this. But the core development team doesn't plan to officially start this until 23 May.