Add MiRNA test for log intensity.
Add MRNA test for log intensity.

Dubious adding of 'scale: 4' to the domain model. This brings it in line
with the other domain models but really was added because the DELTA
otherwise wasn't big enough.

Some 'LOG_INTENSITY' columns in the database have different types
anyway. Most are NUMBER, some are NUMBER(18,4).
Add metabolomics test for log intensity.