Minetest.conf.example(.extra): Updates due to noise group format

Autogenerate minetest.conf.example to convert noises to the now standard
'group format'.
Delete the now unnecessary minetest.conf.example.extra.

minetest.conf.example.extra

@@ -1,63 +0,0 @@
-#    This file contains information (some of which was previously stored in
-#    minetest.conf.example) that cannot be automatically generated from
-#    builtin/settingtypes.txt.
-#    This file contains a list of settings and their default value for minetest.conf
-
-#    By default, all the settings are commented and not functional.
-#    Uncomment settings by removing the preceding #.
-
-#    minetest.conf is read by default from:
-#    ../minetest.conf
-#    ../../minetest.conf
-#    Any other path can be chosen by passing the path as a parameter
-#    to the program, eg. "minetest.exe --config ../minetest.conf.example".
-
-#    Further documentation:
-#    http://wiki.minetest.net/
-
-
-# Mapgen
-
-# Noise parameters and formats
-
-#    Noise parameters can be specified as a set of positional values, for example:
-#
-#    Offset, scale, (x, y, z spread factors), seed offset, octaves, persistence, lacunarity
-# mgv6_np_terrain_base = -4, 20, (250, 250, 250), 82341, 5, 0.6, 2.0
-#
-#    Or the group format can be used instead, for example:
-#
-# mgv6_np_terrain_base = {
-#    offset      = -4,
-#    scale       = 20,
-#    spread      = (250, 250, 250),
-#    seed        = 82341,
-#    octaves     = 5,
-#    persistence = 0.6,
-#    lacunarity  = 2.0,
-#    flags       = "defaults"
-# }
-#
-#    The advanced settings menu does not yet support the group format.
-#    Only the group format supports noise flags which are needed for eased noise.
-#    Mgv5 uses eased noise for np_ground so this is shown in group format below
-#    and is not present in the advanced settings menu.
-
-# Mapgen v5
-
-#    Noise parameter in group format, unsupported by advanced settings menu but
-#    settable in minetest.conf.
-#    See documentation of noise parameter formats above.
-#
-#    3D noise defining terrain.
-#    type: noise_params
-# mgv5_np_ground = {
-#    offset      = 0,
-#    scale       = 40,
-#    spread      = (80, 80, 80),
-#    seed        = 983240,
-#    octaves     = 4,
-#    persistence = 0.55,
-#    lacunarity  = 2.0,
-#    flags       = "eased"
-# }