add transgenic insertion types to genotype model/SO

Not necessarily exactly the same, but see types from MGI:
spontaneous
chemically induced (all)
chemically induced (ENU)
radiation induced
transposon induced
QTL
transgenic (all)
transgenic (random, expressed)
transgenic (random, gene disruption)
transgenic (Cre/Flp)
transgenic (Transposase)
gene trapped
targeted (all)
targeted (Floxed/Frt)
targeted (Reporter)
targeted (knock-out)
targeted (knock-in)

One of the main features we need to support here is conditional expression and/or tissue specific expression and representation of the transgenic insertion itself relative to the host genotype.