Added the common libraries for the hooks to use

 - bz.sh: functions to query bugzilla
 - conf.sh: configuration amangement functions
 - gerrit.sh: gerrit related functions
 - tools.sh: generic helper functions

Change-Id: I7a10060cff5c25e8bd8e2f73654208a90cec70d8
Signed-off-by: David Caro <dcaroest@redhat.com>