CADC_DP: add data reduction script name options

The create_recipe_instance and query_dpstate subroutines
have been modified to allow the name of the data reduction
wrapper script to be specified, in case it should be something
other than "jsawrapdr".
jsawrapdr: correct documentation of -ut option
jsawrapdr: add missing full stop
jsawrapdr: correct case of ORAC-DR
jsawrapdr: correct case of PICARD
jsawrapdr: correct case of FITS
jsawrapdr: extract logging subroutines
jsawrapdr: extract run_pipeline subroutine
jsawrapdr: correct comment for dpCapture part

This bit of the code runs dpCapture, not dpRetrieve.
jsawrapdr: extract capture_products subroutine
jsawrapdr: extract clean_directory subroutines
jsawrapdr: extract prepare_environment subroutine

It's not obvious why this was previously in a BEGIN block.
Since that does not appear to be necessary the subroutine
call has been placed after the option handling.
jsawrapdr: extract retrieve_data subroutine
jsawrapdr: correct documentation of %existing_files

This is not used to determine which files not to delete, so
altered the comment which claimed that it is.
jsawrapdr: break long lines
jsawrapdr: remove tabs
jsawrapdr: extract prepare_environment_cadc