Add menu items for up and refresh

We have installed the signal handlers directly on the existing toolbar
items. Use actions instead so that we can add menu items with the same
functionality and behaviour without having to duplicate the same logic
for all of them; just connect each one of them to the same action and
update the action.

One example of where this is useful is the up button which we only
enable if there's more than one view in the view stack. Using actions we
can update the action and have all widgets connected to that action
updated at the same time.

Signed-off-by: Marcus Karlsson <mk@acc.umu.se>