WebClient shares: add a logout button

Signed-off-by: Nicola Murino <nicola.murino@gmail.com>

internal/httpd/webadmin.go

@@ -151,6 +151,7 @@ type basePage struct {
 	HasSearcher         bool
 	HasExternalLogin    bool
 	LoggedUser          *dataprovider.Admin
+	IsLoggedToShare     bool
 	Branding            UIBranding
 }