Update git submodules

* Update docs/submodules/oom/offline-installer.git from branch 'master'
  to a579c98a9ea48b00b38a66ade7e8139e18bf0eae
  - Add helm override instructions to install guide
    
    This commit adds instruction about using the new
    helm chart overrides feature.
    
    Change-Id: I6a5d973ee91562ae618d357fd3fdecc1cf4f03bf
    Issue-ID: OOM-1752
    Signed-off-by: Michal Zegan <m.zegan@samsung.com>
    
diff --git a/docs/submodules/oom/offline-installer.git b/docs/submodules/oom/offline-installer.git
index 53036e8..a579c98 160000
--- a/docs/submodules/oom/offline-installer.git
+++ b/docs/submodules/oom/offline-installer.git
@@ -1 +1 @@
-Subproject commit 53036e8f41f50cb7ebb2346d02442d80bc16ece0
+Subproject commit a579c98a9ea48b00b38a66ade7e8139e18bf0eae