orderbook: consolidate slice array types to orderbook package (#1992)

* orderbook: consolidate slice array types to orderbook package

* Update exchanges/bybit/bybit_types.go

Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>

* linter: fix and add test

* cranktakular: nits

* cranktakular: nits

* Update exchanges/orderbook/orderbook_types.go

Co-authored-by: Gareth Kirwan <gbjkirwan@gmail.com>

* Update exchanges/gateio/gateio_test.go

Co-authored-by: Gareth Kirwan <gbjkirwan@gmail.com>

* gk: nits consolidation

* gk: rm unifySpotOrderbook func

* gk: nit but different

* linter: fix

* gk: nits

* glorious: nits

* Update exchanges/binance/binance.go

Co-authored-by: Adrian Gallagher <adrian.gallagher@thrasher.io>

* Update exchanges/binance/binance_cfutures.go

Co-authored-by: Adrian Gallagher <adrian.gallagher@thrasher.io>

* Update exchanges/binanceus/binanceus.go

Co-authored-by: Adrian Gallagher <adrian.gallagher@thrasher.io>

* thrasher-:nits

* thrasher-: more nit

---------

Co-authored-by: Ryan O'Hara-Reid <ryan.oharareid@thrasher.io>
Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>
Co-authored-by: Gareth Kirwan <gbjkirwan@gmail.com>
Co-authored-by: Adrian Gallagher <adrian.gallagher@thrasher.io>

exchanges/bitstamp/bitstamp_test.go

@@ -197,7 +197,7 @@ func TestGetOrderbook(t *testing.T) {
 	ob, err := e.GetOrderbook(t.Context(), currency.BTC.String()+currency.USD.String())
 	require.NoError(t, err, "GetOrderbook must not error")
 	assert.NotEmpty(t, ob.Timestamp, "Timestamp should not be empty")
-	for i, o := range [][]OrderbookBase{ob.Asks, ob.Bids} {
+	for i, o := range [][]orderbook.Level{ob.Asks, ob.Bids} {
 		s := []string{"Ask", "Bid"}[i]
 		if assert.NotEmptyf(t, o, "Should have items in %ss", s) {
 			a := o[0]