Misc: Update copyright dates (bnc#804726)

Signed-off-by: Tim Serong <tserong@suse.com>
Doc: TODO: Note about dashboard not supporting url_root

Signed-off-by: Tim Serong <tserong@suse.com>
GUI: dashboard: Allow ENTER to trigger OK button when adding cluster

Signed-off-by: Tim Serong <tserong@suse.com>
GUI: dashboard: Don't allow adding the same cluster twice (bnc#806076)

Signed-off-by: Tim Serong <tserong@suse.com>