README stored on disk is out of date/confusing

[aschmahmann]

The README is misleading

go-ds-flatfs/readme.go

Lines 3 to 33 in f075020

	var README_IPFS_DEF_SHARD = `This is a repository of IPLD objects. Each IPLD object is in a single file,
	named <base32 encoding of cid>.data. Where <base32 encoding of cid> is the
	"base32" encoding of the CID (as specified in
	https://github.com/multiformats/multibase) without the 'B' prefix.
	All the object files are placed in a tree of directories, based on a
	function of the CID. This is a form of sharding similar to
	the objects directory in git repositories. Previously, we used
	prefixes, we now use the next-to-last two characters.
	func NextToLast(base32cid string) {
	nextToLastLen := 2
	offset := len(base32cid) - nextToLastLen - 1
	return str[offset : offset+nextToLastLen]
	}
	For example, an object with a base58 CIDv1 of
	zb2rhYSxw4ZjuzgCnWSt19Q94ERaeFhu9uSqRgjSdx9bsgM6f
	has a base32 CIDv1 of
	BAFKREIA22FLID5AJ2KU7URG47MDLROZIH6YF2KALU2PWEFPVI37YLKRSCA
	and will be placed at
	SC/AFKREIA22FLID5AJ2KU7URG47MDLROZIH6YF2KALU2PWEFPVI37YLKRSCA.data
	with 'SC' being the last-to-next two characters and the 'B' at the
	beginning of the CIDv1 string is the multibase prefix that is not
	stored in the filename.
	`

FlatFS does not know anything about CIDs, blocks or IPLD and actually is being used by different projects in the ecosystem in different ways. In particular some key their IPLD blocks by CIDs and some by multihashes, but FlatFS doesn't really care. All the text around base32 encoding, CIDs, etc. should be removed and placed into the docs of the applications that use them (e.g. go-ipfs docs).