style: sort imports in api and utils modules

gns3server/utils/cpu_percent.py

@@ -14,9 +14,10 @@
 # You should have received a copy of the GNU General Public License
 # along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
-import psutil
 import time
 
+import psutil
+
 
 class CpuPercent:
     """