path for the riseupvpn.svg

Right now the systray expects to find riseupvpn.svg (used for the notifications) in the same folder that it's being executed from.

@kali is that a right assumption? I guess it is for the bundles, or maybe we want to place in a subfolder somewhere. But what about debian packages? Where it will be placed in this case? I could try first to load from the bundle path and if it fails try with the system path.