Parse clients data for bridges

Onionoo provides another API method for bridges - information about
clients that used the bridge. Let Atlas provide average client count
graphs.

Signed-off-by: Dmitry Eremin-Solenikov <dbaryshkov@gmail.com>
Add type column to search view

Add a column representing router type (Bridge/Router) to the search
view.

Signed-off-by: Dmitry Eremin-Solenikov <dbaryshkov@gmail.com>