Add the ability to copy a custom field context

Please add the ability to copy custom field contexts.

I am configuring a new custom field which requires a different context for each project. The contexts are pretty similar but include many multi level cascade select options (plugin). As each context is similar it would be so much easier to be able to set up a context for a single project and then copy that context for each other project altering the required options as necessary. Currently I have to recreate the same context many times (taking me 10 min for each context) where as if I could copy the context it would take me less than a minute each.

I'm (hopefully) only doing this once so unless there is an existing method a fix won't really help me but it may help others or even myself if I'm unfortunate enough to have to configure multiple contexts again in the future.