Subscribe to Telegram event through config file

[Lntnam]

Short Description

At the moment Telegram task allows us to subscribe through command /sub.
It'd be better if we can pre-set the subscription through config file, say telegram.json.

Possible solution

Modify the task construction/initialization to parse the config, and perform necessary subscription.

How it would help others

People are interested in only a certain set of events, and that's unlikely to change. Hence having to re-sub one by one every time restart the bot would be very troublesome.

Config file would be the starting point, then we can still subscribe for more as per usual.

[avexus]

I think we don't need another conf file. We can do this in auth.json @lntn

[javajohnHub]

The subs are saved in a database....you shouldnt have to resubscribe everytime you start the bot.