Showing configuration tab of deployed overcloud

-showing configuration from heat
-test for configuration tab
-test for event logs was missing, so I've added it too
-fixing test for mocking only needed values
-all tabs set to preload=False
-extracting deCamelCase into utils and changed 2 usages

Change-Id: I312bbc6e47137e5184bcb60963472c55388b64e6
Merge "Showing configuration tab of deployed overcloud"