Update git submodules

Update git submodules

* Update docs/submodules/oom/offline-installer.git from branch 'master'
  to cb94aefb4ef22fdf435578e676823a6b9600cbb9
  - Merge "Replace VNC server docker image"
  - Replace VNC server docker image

    Replace VNC server docker image based on CentOS
    (consol/centos-icewm-vnc:1.4.0) by the one based on
    Ubuntu (consol/centos-icewm-vnc:1.4.0) - Ubuntu based image is smaller
    and the VNC server does not work in the current CentOS based image.

    Solves OOM-1819

    Issue-ID: OOM-1821

    Change-Id: I9e06ab8bfccb11ae8950717db5339062704a31f9
    Signed-off-by: Tomáš Levora <t.levora@partner.samsung.com>