Project: bamboo
Issue BAM-5218: When downsizing a license plans users are directed to delete on the _old_  server 
When a user has to downsize bamboo instance the use is directed to a delete plans screen. The link points to the bamboo server the last export was made from. Plans on the _previous_ server are deleted _not_ on the current. The previous server may still be active and eligible to run unlimited plans. On that screen a neon warning should be displayed and the base url should be questioned (if not the same as the current hostname/ip address)
Story points: 3