sim_fibo_ad: convert to the new-style wells manager

i.e. it now uses Opm::EclipseState. This change required to re-add the
the epoch concept in some sense, but the loop variables now call it
"episode" which sounds less ethernal IMO.
sim_fibo_ad: fix writing

the initial condition was written multiple times. We now fix this by
not writing anything in the simulator and moving this logic to the
main loop..