put test data in a dedicated namespace

I am afraid that if there's no clear 'architecture' for data, this
folder will rapidly become a mess. These data are strictly related
to the BinarySpec so, let's make it obvious from the folder
architecture and the file names.

test/unit/Cardano/Wallet/BinarySpec.hs

@@ -36,22 +36,22 @@ spec :: Spec
 spec = do
     describe "Decoding blocks" $ do
         it "should decode a block header" $ do
-            bs <- L8.readFile "test/data/block-header-1"
+            bs <- L8.readFile "test/data/Cardano/Wallet/BinarySpec-block-header-1"
             let decoded = unsafeDeserialiseFromBytes decodeBlockHeader bs
             decoded `shouldBe` blockHeader1
 
         it "should decode a block without transactions" $ do
-            bs <- L8.readFile "test/data/block-1"
+            bs <- L8.readFile "test/data/Cardano/Wallet/BinarySpec-block-1"
             let decoded = unsafeDeserialiseFromBytes decodeBlock bs
             decoded `shouldBe` block1
 
         it "should decode a block with transactions" $ do
-            bs <- L8.readFile "test/data/block-2"
+            bs <- L8.readFile "test/data/Cardano/Wallet/BinarySpec-block-2"
             let decoded = unsafeDeserialiseFromBytes decodeBlock bs
             decoded `shouldBe` block2
 
         it "should decode a testnet block with a transaction" $ do
-            bs <- L8.readFile "test/data/block-3"
+            bs <- L8.readFile "test/data/Cardano/Wallet/BinarySpec-block-3"
             let decoded = unsafeDeserialiseFromBytes decodeBlock bs
             decoded `shouldBe` block3