[telegram] add setting to ignore low amount keysends

[alexbosworth]

If you are getting keysend spam at N amount, where N is lower than what you want to see, do not notify the telegram bot

[brianoflondon]

Greatly needed. This stupid 1 sat / low sat spam is getting insane.

Perhaps also consider detecting http links and allowing for blocking those as that seems to be a common part of this spam.

[alexbosworth]

I think telegram has some formatting options for how it treats links so it wouldn't auto preview them, that might help