API incubator feature toggles
Converter tree re-reads value after create/update
Allow read access to known metadata values
Use StorageException for errors
Builtin plugin type to require ssh key content types
Add base /ssh-key converter plugin to require content types
Change url mapping for ssh-key and incubator resources to use /storage
Add sshKey resource path action
Resource metadata response uses actual metadata keys
Handle StorageExceptions from service layer
avoid NPE when sanitizing json data map