Add gluon integration tests to gitlab ci

6 jobs for integrate-gluon-backend in 11 minutes and 7 seconds
Status Job ID Name Coverage
  Windows
passed #309595
Windows10
masterJobWindows

00:04:33

failed #308515
Windows10
masterJobWindows

00:00:01

 
  Linux
passed #308517
integrationCaffe2JobLinux

00:06:34

passed #308518
integrationGluonJobLinux

00:06:19

passed #308516
integrationMXNetJobLinux

00:06:24

passed #308519
UnitTestJobLinux

00:06:24