Extract blocks/blockstore package to go-ipfs-blockstore

This extracts the blocks/blockstore package and renames the
blocks/blockstore/util package to /blocks/blockstoreutil
(because util depends on Pin and I don't plan to extract
Pin and its depedencies).

The history of blocks/blockstore has been preserved. It has
been gx'ed and imported. Imports have been rewritten accordingly
and re-ordered.

License: MIT
Signed-off-by: Hector Sanjuan <hector@protocol.ai>

test/utils.go

 package mdutils
 
 import (
-	"github.com/ipfs/go-ipfs/blocks/blockstore"
 	bsrv "github.com/ipfs/go-ipfs/blockservice"
 	"github.com/ipfs/go-ipfs/exchange/offline"
 	dag "github.com/ipfs/go-ipfs/merkledag"
 
 	ds "gx/ipfs/QmPpegoMqhAEqjncrzArm7KVWAkCm78rqL2DPuNjhPrshg/go-datastore"
 	dssync "gx/ipfs/QmPpegoMqhAEqjncrzArm7KVWAkCm78rqL2DPuNjhPrshg/go-datastore/sync"
+	blockstore "gx/ipfs/QmTVDM4LCSUMFNQzbDLL9zQwp8usE6QHymFdh3h8vL9v6b/go-ipfs-blockstore"
 	ipld "gx/ipfs/Qme5bWv7wtjUNGsK2BNGVUFPKiuxWrsqrtvYwCLRw8YFES/go-ipld-format"
 )
 

utils/utils.go

@@ -4,7 +4,6 @@ import (
 	"context"
 	"errors"
 
-	bstore "github.com/ipfs/go-ipfs/blocks/blockstore"
 	bserv "github.com/ipfs/go-ipfs/blockservice"
 	offline "github.com/ipfs/go-ipfs/exchange/offline"
 	dag "github.com/ipfs/go-ipfs/merkledag"
@@ -12,6 +11,7 @@ import (
 
 	ds "gx/ipfs/QmPpegoMqhAEqjncrzArm7KVWAkCm78rqL2DPuNjhPrshg/go-datastore"
 	syncds "gx/ipfs/QmPpegoMqhAEqjncrzArm7KVWAkCm78rqL2DPuNjhPrshg/go-datastore/sync"
+	bstore "gx/ipfs/QmTVDM4LCSUMFNQzbDLL9zQwp8usE6QHymFdh3h8vL9v6b/go-ipfs-blockstore"
 	ipld "gx/ipfs/Qme5bWv7wtjUNGsK2BNGVUFPKiuxWrsqrtvYwCLRw8YFES/go-ipld-format"
 )