Underch mod marble compatibility

[nonfreegithub]

underch is a popular cave improvement mod that adds marble and marble bricks (same as technic) but also stairs, slabs, marble cobble, mossy marble cobble, etc.

I have seen some servers where both mods are used and I thought it would be good to add this little compatibility

[OgelGames]

Makes sense to me 👍

One small thing, the has_underch variables are only used once in each file, so I think it would be better just to use minetest.get_modpath("underch") where needed, rather than add those extra variables.

[nonfreegithub]

I dont know if underch must be in optional_depends, it can cause circular depends issues

[BuckarooBanzay]

I dont know if underch must be in optional_depends, it can cause circular depends issues

Should not be an issue, the technic mod isn't required in the underch mod:
https://gitlab.com/h2mm/underch/-/blob/master/mod.conf?ref_type=heads