Extend (Multi) Url Picker with allow internal, external & media link switches

[martinlcp]

Can the (multi) Url picker datatype be extended so that you can choose what type of urls can be picked?

i.e. add switches so that you can pre-determine whether a content editor can choose from:

1. External urls
2. internal urls (picker with search)
3. internal media urls (select media)

This UI can be sometimes be too much for what's needed and I have lazy content editors who "copy and paste" absolute URLs from the content managed site into the external url box instead of using the tree picker!