Assign study id(s) to sample metadata, IMPACT/HemePACT data sets mostly

[allanbolipata]

Assign a default study id to samples based on "set_" + labHeadEmail (without characters after @).

Need to be able to assign multiple study ids to a sample.

Other possibility that must be considered is to assign a study id based on project name (i.e., the number portion of the request ID; for example, if project 12345 samples should go to study set_blahblah, any samples in requests with 12345_* should be assigned the study id set_blahblah).

@timosong do you have any other cases that need to be covered?