Convert static methods to top-level functions

The publish and creates_conflicts class methods in util.py would
be better implemented as top-level functions. Having these
methods as static class methods would be unnecessary and would
require instantiating a MeetingUtil object in order to invoke
them. Top-level functions would be simpler and would still
provide the required functionality.

Change-Id: I75523d47ce57b28118398a5ea9bf29fda398c807