OrderBook: allow dex_id = 1

[wer1st]

Now the creation of order-book is allowed only for dex_id = 0, where XOR is a base asset of dex and accordingly it is a quote asset for all order-books. The base asset of dex with dex_id = 1 is XSTUSD. If we allow to create order-books with dex_id = 1 we could have pairs to Sora stablecoin XSTUSD. It could be more interesting for users.

@Tieumsan please review