[6.0] Global.deserializeTo[] method

[kushti]

This PR contains new Global.deserializeRaw method which is allowing to deserialize a typed object from underlying type bytes (see below).

Types supported are:

• Short - deserialization is from 2 (big-endian) bytes (Short JVM type big-endian serialization)
• Int - deserialization is from 4 (big-endian) bytes (Int JVM type big-endian serialization)
• Long - synonym of Global.byteArrayToLong
• BigInt - synonym of Global.byteArrayToBigInt
• Box - deserialization is from ErgoBox bytes (ErgoBox.sigmaSerializer.toBytes(box))
• GroupElement - deserialization works for serialized secp256k1 points (33 bytes)
• SigmaProp - deserialization works only for fully evaluated (cryptographic) trees (e.g. SigmaPropConstant(CSigmaProp(CAND(Seq(dlogSecrets(0).publicImage, dhSecrets(0).publicImage))))
• AvlTree - deserialization works for avl tree fields (digest, modification flags, key length, value lentgh), see AvlTreeData.serializer.serialize() for serialization
• Header - deserialization works for ErgoHeader bytes

examples:

{
    val ba = fromBase16("028a5b7f7f7f7f7f7f6c");
    val b = Global.deserialize[BigInt](ba)
    b == byteArrayToBigInt(ba)
}

{
    val ba = getVar[Coll[Byte]](21).get
    val prop = Global.deserialize[SigmaProp](ba)
    prop
}

The method is called deserializeRaw as we may have deserializeTyped as well in future (to deserialize data with type information attached, e.g. Coll[Header])