Add GetOrCreate methods to components

Instead of creating components in Create() methods we can now just
try to get them and let the API create them if they do not exist.

Signed-off-by: Patrik Jakobsson <patrik.r.jakobsson@gmail.com>
Add AutoDelete method to Contents API

Most of the time the API core can figure out what needs to be deleted.

Signed-off-by: Patrik Jakobsson <patrik.r.jakobsson@gmail.com>