WIP: Change default distance when using margdist

For an 3G study I'm working on I wanted to use the --margdist option. But my error output files are filling up with lines like

XLAL Error - LALInferenceMarginalDistanceLogLikelihood (LALInferenceLikelihood.c:1355): warning: Optimal SNR 255874.745891 exceeded pmax 100000.000000

This since when using the distanceMarginalisedLikelihood (which removes the logdistance as a varied/sampled parameter) uses a default distance of 1 Mpc for the WF calculation.

I'd suggest changing this default to 100 Mpc which should reduce the cases where the OptimalSNR becomes ridiculously big (setting loglikelihood=-INF) for 3G studies. It's also a reasonable number for use in current O3 analyses since LIGO detectors now are both at that range for effectively all CBC signals we think we'll be observing.