[FEATURE REQUEST] Dedicated folder for sample groups.

[MarioFanGamer]

In order to aid the insertion of sample groups (which have become fairly popular lately but did cause at least one case of confusion), I suggest the use of a folder where individual sample are placed into their own files which AMK which doesn't require users to play around with Addmusic_sample groups.txt.

In an ideal world (i.e. my preferred method), the sample groups would be generated by reading a text document with a list of samples (and only samples i.e. stripped of brackets and name) to create the sample group with the filename being used as the sample group name (e.g. a file with all the vanilla samples listed in the order as they exist in the vanilla game in a TXT named default is equivalent to current #default) but that doesn't play nicely with backwards compatibility so the individual files should be in the same format as Addmusic_sample groups.txt for now (and possibly with a warning that the sample group differs from the filename and that multiple groups are included in a single file).