[Enhancement] Have a notification center that notifies users of new coins listed on exchanges

[caogeoge]

Hi Sjakil,

As a follow-up to my previous enhancement request (#21), I think it would be great if whenever users launch the Gunthy GUI webpage, it notifies users of new pairs being added to the corresponding exchanges (that they have not yet added to their bots). If possible we can also show the curves/graphs of these new pairs in a small section somewhere in the interface. This way users are aware of new cool coins that they might have been missing to add to their GunBots.