Add additional link to PA tweets

[Sportsbadger]

I'd like to include an additional link in my PA DM's - this could be to a picture or a wiki page. Basically a link that explains why the aircraft is interesting.
Maybe a specific header could be used in the plane-alert-db.txt file to define the field that is to be linked. I would add these to my online list (either full URLs or already shortened) and then users could edit to add their own links.

[kx1t]

This was implemented a while ago