cockpit-client: Use a property binding for title
cockpit-client: Use a property binding for title

Fix a bug where the title only changes when the page changes: directly
bind the title property of the webview to the window.

cockpit-project/cockpit,cockpit-project/cockpit,cockpit-project/cockpit,cockpit-project/cockpit,martinpitt/cockpit,mvollmer/cockpit,martinpitt/cockpit,mvollmer/cockpit,martinpitt/cockpit,mvollmer/cockpit,cockpit-project/cockpit,mvollmer/cockpit,mvollmer/cockpit,martinpitt/cockpit,martinpitt/cockpit