Add setting to change the inflation destination

Add a setting that shows and changes the inflation destination.

Fixes #596.

TODO: Federate the default inflation address.
Lets do that for now... I think going forward we need to re-think how we share code more effectively in Angular.  It could be simply implemented as a service as well, but I don't yet have a good sense about what is most in line with  the expectations of a developer coming fresh into the codebase.