Settings: Make setting entry group and values mutually exclusive

This greatly reduces the complexity of Settings code.
Additionally, several memory leaks were fixed.
Rename and repurpose minetest.set_noiseparam_defaults to set_noiseparams
Settings: Sanitize setting name everywhere, not just LuaSettings
Noise: Create a deep copy of NoiseParams
Remove get_noiseparams function. read_noiseparams should be used from now on
Add paste command (Ctrl-V) in GUIChatConsole
Add support for lacunarity in legacy NoiseParams string format
Biome API: Reduce heat and humidity persistences to 0.5
Move get_schematic and read_schematic to l_mapgen.cpp
Merge remote-tracking branch 'minetest/master' into stable

Conflicts:
	src/mapgen.h
	src/mapgen_v6.cpp
	src/mapgen_v7.cpp
	src/noise.cpp
	src/settings.cpp
fix: merge