Update config to enable custom app navigation

- Update documentation to include navigation customizations
- Created an IBM specific application navigation file to demonstrate
  how to remove KVM navigation item

Signed-off-by: Yoshie Muranaka <yoshiemuranaka@gmail.com>
Change-Id: I2ea61e9f3a43e6821f274ed90e0eed18afabccb7
diff --git a/.env.ibm b/.env.ibm
index 2d47ae9..b781328 100644
--- a/.env.ibm
+++ b/.env.ibm
@@ -1,4 +1,5 @@
 NODE_ENV=production
 VUE_APP_ENV_NAME=ibm
 VUE_APP_COMPANY_NAME="IBM"
-CUSTOM_STYLES=true
\ No newline at end of file
+CUSTOM_STYLES=true
+CUSTOM_APP_NAV=true
\ No newline at end of file