Replacing recursive opendir with a utility function

Replacing recursive opendir with a utility function

[Issue#] N/A
[Feature] Replacing recursive opendir with safer utility function
[Cause] Recursive opendir may reach limit of open dirs for process
[Solution] Replace with a utility function
[Verification] Uninstall widget, verify that installation directory was removed

Installer removes the widget installation directory, which can have multiple
levels of directories. Instead of recursively calling opendir, installer will
now call WrtUtilRemove function that uses safe fts_* functions to traverse the
directory tree.

Change-Id: I3ff7e02b32c76da37785f6d6b793e19bca308ae1