Adds concrete powder/anvil to no-physics-config

[aurorasmiles]

Fixes #1411
This feels like something often requested in Discord. There are in theory a couple more blocks that can be affected by gravity, but most of those seem like edge cases that are rarely relevant (except the dragon egg maybe, but I feel like the dragon egg has a lot more annoying things to block before gravity)

[wizjany]

I've been mentally pushing this off every time someone asks because I feel like adding a million config options isn't the way to go long-term. Perhaps it's better to have a list like the water/lava/fire spread configs?

[aurorasmiles]

I feel like lists like that are generally the way to go, but only if we support block tags on those lists as well. I don't want users to have to add all concrete powder variants to a list when adding ##concrete_powder might be possible

[InstantlyMoist]

This seems fine for now no? Better than nothing and having to make/install another plugin just for this.