[h3mlib] Conversion: Fix conversion of RoE-compatible Seer's Huts

[potmdehex]

AB/SoD maps allow for more quest types than RoE. Currently all Seer's Huts are dropped during conversion, including the ones that have the basic Return with artifact quest type that is compatible with RoE. Seer's Huts that have this quest type should be converted and kept.

Code: https://github.com/potmdehex/homm3tools/blob/master/h3m/h3mlib/h3m_conversion/convert.c

Done definition: RoE-compatible Seer's Huts on non-RoE maps should be converted and kept after conversion to RoE.

Note: The h3m conversion code in h3mlib was mostly written in a rush a few days before HD Edition's release so it is quite messy.