Update following JAC's removal of CABLE science code

As part of the change of licence for JULES, it was decided that JAC would be pursued by keeping the CABLE code in its own repository and connecting the two code sources at compilation time.

As a consequence, the CABLE code as well as some interface code added to JULES has been removed for version 4.0. This issue is to add that code to this repository as necessary since it will be its new home.