qb: Added shortcuts to Queryx

It allows to write shorter and more straightforward code.
Instead writing:

```
session.Query(qb.Select("cluster").Columns("id").ToCql())
```

you can write:

```
qb.Select("cluster").Columns("id").Query(session)
```

qb/batch.go

@@ -8,6 +8,8 @@ import (
 	"bytes"
 	"fmt"
 	"time"
+
+	"github.com/scylladb/gocqlx/v2"
 )
 
 // BATCH reference:
@@ -64,6 +66,11 @@ func (b *BatchBuilder) ToCql() (stmt string, names []string) {
 	return
 }
 
+// Query returns query built on top of current BatchBuilder state.
+func (b *BatchBuilder) Query(session gocqlx.Session) *gocqlx.Queryx {
+	return session.Query(b.ToCql())
+}
+
 // Add builds the builder and adds the statement to the batch.
 func (b *BatchBuilder) Add(builder Builder) *BatchBuilder {
 	return b.AddStmt(builder.ToCql())

qb/delete.go

@@ -10,6 +10,8 @@ package qb
 import (
 	"bytes"
 	"time"
+
+	"github.com/scylladb/gocqlx/v2"
 )
 
 // DeleteBuilder builds CQL DELETE statements.
@@ -54,6 +56,11 @@ func (b *DeleteBuilder) ToCql() (stmt string, names []string) {
 	return
 }
 
+// Query returns query built on top of current DeleteBuilder state.
+func (b *DeleteBuilder) Query(session gocqlx.Session) *gocqlx.Queryx {
+	return session.Query(b.ToCql())
+}
+
 // From sets the table to be deleted from.
 func (b *DeleteBuilder) From(table string) *DeleteBuilder {
 	b.table = table

qb/insert.go

@@ -10,6 +10,8 @@ package qb
 import (
 	"bytes"
 	"time"
+
+	"github.com/scylladb/gocqlx/v2"
 )
 
 // initializer specifies an value for a column in an insert operation.
@@ -78,6 +80,11 @@ func (b *InsertBuilder) ToCql() (stmt string, names []string) {
 	return
 }
 
+// Query returns query built on top of current InsertBuilder state.
+func (b *InsertBuilder) Query(session gocqlx.Session) *gocqlx.Queryx {
+	return session.Query(b.ToCql())
+}
+
 // Into sets the INTO clause of the query.
 func (b *InsertBuilder) Into(table string) *InsertBuilder {
 	b.table = table

qb/select.go

@@ -10,6 +10,8 @@ package qb
 import (
 	"bytes"
 	"fmt"
+
+	"github.com/scylladb/gocqlx/v2"
 )
 
 // Order specifies sorting order.
@@ -118,6 +120,11 @@ func (b *SelectBuilder) ToCql() (stmt string, names []string) {
 	return
 }
 
+// Query returns query built on top of current SelectBuilder state.
+func (b *SelectBuilder) Query(session gocqlx.Session) *gocqlx.Queryx {
+	return session.Query(b.ToCql())
+}
+
 // From sets the table to be selected from.
 func (b *SelectBuilder) From(table string) *SelectBuilder {
 	b.table = table

qb/update.go

@@ -10,6 +10,8 @@ package qb
 import (
 	"bytes"
 	"time"
+
+	"github.com/scylladb/gocqlx/v2"
 )
 
 // assignment specifies an assignment in a set operation.
@@ -73,6 +75,11 @@ func (b *UpdateBuilder) ToCql() (stmt string, names []string) {
 	return
 }
 
+// Query returns query built on top of current UpdateBuilder state.
+func (b *UpdateBuilder) Query(session gocqlx.Session) *gocqlx.Queryx {
+	return session.Query(b.ToCql())
+}
+
 // Table sets the table to be updated.
 func (b *UpdateBuilder) Table(table string) *UpdateBuilder {
 	b.table = table