Add schema rename support

Using SchemaFrom("schemaName") it is possible to set SQL builder table to point to a different schema.

postgres/dialect_test.go

@@ -80,13 +80,7 @@ func TestReservedWordEscaped(t *testing.T) {
 	var table1ColVariadic = IntervalColumn("VARIADIC")
 	var table1ColProcedure = IntervalColumn("procedure")
 
-	_ = NewTable(
-		"db",
-		"table1",
-		table1ColUser,
-		table1ColVariadic,
-		table1ColProcedure,
-	)
+	_ = NewTable("db", "table1", "", table1ColUser, table1ColVariadic, table1ColProcedure)
 
 	assertSerialize(t, table1ColUser, `table1."user"`)
 	assertSerialize(t, table1ColVariadic, `table1."VARIADIC"`)