Allow creation of bookmarks from web vault settings

Hi,

a few days ago I stumbled upon your project and thought, that it might be handy to be able to create bookmarkable URLs for the settings one uses for services.

This pull request adds a simple GET form and submit button with repopulation of query string parameter values onto the existing form input fields via javascript (apart from the passphrase inputs of course). The service name will be put into the URL as well and will be prepended to the page title to make bookmarking a bit easier for different service names.

The code uses [querySelector](http://caniuse.com/#feat=queryselector) to select the inputs. Mind you, I only changed the `web`/`lib` code and did not have a look at the `chrome` extension folder as I don't know what the status of that is.

Thanks for your effort. I'm really thinking about to use it... :+1: 

Kind regards,

Steffen