Image block - add object-position control if object-fit option is used.

[eastriverstudio]

I'd like to suggest a small and hopefully simple enhancement to the image block's current object-fit option.

Sometimes when using object-fit it is also desirable to control the positioning using object-position. This is particularly helpful when using the cover option to help with cropping nicely.

I'd suggest it works similar to the current background position field on containers which has the default value to start off but then we can manually type in a desired custom value e.g "center top" if we prefer to change the position.

Thanks