Decide how sample identifiers are handled

[dfornika]

Users may wish to use separate sample identifiers for uploaded samples than those used in IRIDA.

What should the default behaviour be?

How can users provide alternative sample IDs? From a metadata field? A pre-defined field, or a user-specified one?

Should fastq files also be renamed to use the alternate sample IDs?

[dfornika]

After discussion, decided that the ID will be pulled from a user-configurable metadata field, defaulting to library_name