LPS-44944 Move methods in WikiUtil to WikiSettings. @Brian: note that the _fallbackKeys map in WikiSettings is formatted differently from the one in MBSettings. This is intentional because this map represents the chaining to follow when searching for properties. Thus, for example, when getting the property "emailFromAddress", the fallback mechanism will look in PropsKeys.WIKI_EMAIL_FROM_ADDRESS if the former is not found. If it still not found, it will jump again from PropsKeys.WIKI_EMAIL_FROM_ADDRESS to  PropsKeys.ADMIN_EMAIL_FROM_ADDRESS (as declared in the second line of the map). Then there's an empty line to denote a new chain start and so on. If you still don't like this formatting, we can try to abstract the chaining concept in a specific class to make this relation more evident.
LPS-44944 Totally remove PortletPreferences (in favor of WikiSettings) from the wiki portlet
LPS-44944 SF: Keep code more similar to the previous code and move generic method to ArrayUtil
LPS-44944 Move Wiki configuration from wiki to wiki_admin portlet
LPS-44944 Make wiki_admin configuration page save settings where they belong
LPS-44944 Remove all references to PortletPreferences (in favor of Settings) from all JSPs
LPS-44944 Move all (possible) defaults from WikiSettings to portal.properties
LPS-44944 Avoid hardcoding "magic" default values in WikiSettings.

We assume that the default must *always* be set in portal.properties
LPS-44944 Order used
LPS-44944 SF