Allow selecting channels with selectChats() and sendToActiveChats()

[jacklul]

This can be particulary useful now since bots can receive channel messages.

I hope I didn't miss anything, I guess travis will tell...

[noplanman]

This is screaming for bit flags / bitmask:
https://stackoverflow.com/questions/11880360/how-to-implement-a-bitmask-in-php

Having so many boolean parameters is just waaay confusing 😖

[jacklul]

Well, I think I have no clue how to do this in a clean way, I would have to declare those somewhere, but where to make them accessible at all time?

[noplanman]

An option could be to just pop them into the DB class:

const SINGLE_CHAT = 1;
const GROUP_CHAT = 2;
const SUPERGROUP_CHAT = 4;
const CHANNEL = 8;

But this may seem a bit confusing 😕

Probably makes sense to do the same here like with other parameters, passing the values as an array (as described further down from my link above: https://stackoverflow.com/a/29089798):

$results = DB::selectChats([
    'groups'       => true,
    'supergroups'  => true,
    'channels'     => true,
    'single_chats' => true, // or 'user_chats', or just 'single'?
    'date_from'    => 'yyyy-mm-dd hh:mm:ss', // or better, use DateTimeImmutable objects
    'date_to'      => 'yyyy-mm-dd hh:mm:ss',
]);

[noplanman]

@jacklul Have made a PR to your PR that implements the solution with the array, please check it out when you have a moment, thanks.