Fix approve transfer API

MicroServiceChainChoice had been updated to have a foreign key to MicroServiceChain, but not all cases that used chainavailable were updated.  Fixed the last one.

Other cleanup while fixing this:
* Add instructions to API whitelist template specifying the format
* Whitelisted IPs for API are now whitespaces separated, instead of \r\n
* Clean up import list
* Add logging
* Add unicode function to MicroServiceChain & MicroServiceChainChoice

Supports artefactual/archivematica-storage-service#7