mass distribustion of .ssh/authorized_keys

[samwyse]

I've got a bunch (in the double digits) of routers and switches that
all support ssh/scp access. I'd like to set them up with my public
key without having to type my password in for each box. Before I
write a script, I thought I'd see if anyone's done this before. Note
that you can't assume that the targets provide anything beyond scp.
Bonus points if you don't destroy any pre-existing information, which
will be useful if/when we need to add someone else to the file.