An invalid checksum algorithm in the -R should cause the list of defined algorithm to be show

Currently the user has to refer to the documentation to view the available options. It would be much user friendly to print the valid algorithm options in response to a invalid argument, same as for the pillar and colelction arguments

The current error message

Invalid argument: No enum constant org.bitrepository.bitrepositoryelements.ChecksumType.sha1

should at the same time be changed to to something more human readable, f.ex sha1 is not a valid checksum type, valid values are: .......

Should also consider ignoring casing in the the argument -R when looking it up in the ChecksumType list. There should not ne any difference between sha, SHA1 and sHa1.