store used data transfer as big integer

we originally stored these values as MB but since we use bytes now,
an integer field is not enough.

Fixes #1575

Signed-off-by: Nicola Murino <nicola.murino@gmail.com>

internal/dataprovider/sqlcommon.go

@@ -35,7 +35,7 @@ import (
 )
 
 const (
-	sqlDatabaseVersion     = 28
+	sqlDatabaseVersion     = 29
 	defaultSQLQueryTimeout = 10 * time.Second
 	longSQLQueryTimeout    = 60 * time.Second
 )