Adding features to main features.xml in integration repo

Adding features to main features.xml in integration repo

1) Feature Tests Pass: https://jenkins.opendaylight.org/releng/view/didm/job/didm-merge-master/lastBuild/testReport/
2) Features Comply with Guidelines: https://git.opendaylight.org/gerrit/gitweb?p=didm.git;a=blob;f=features/src/main/features/features.xml
   a) Feature Names (prefixed with 'odl-'): odl-didm-identification-api, odl-didm-identification, odl-didm-drivers-api (check https://wiki.opendaylight.org/view/Runtime:Karaf_Features_Guidelines#Feature_Naming)
   b) Features Descriptions: Present (check https://wiki.opendaylight.org/view/Runtime:Karaf_Features_Guidelines#Description)
   c) Features Start-Levels: None
3) Features Tested: Features have been tested for functionality with
   a) feature:install odl- didm-identification-api
   b) feature:install odl- didm-identification
   c) feature:install odl- didm-drivers-api
   d) feature:install odl- didm-identification-api, didm-identification, didm-drivers-api, odl-integration-compatible-with-all
4) Integration Test Impact: None

Change-Id: Ieb2617a5c44396630bab7a3a792fcec189dfe2b8
Signed-off-by: Steve Dean <sdean@hp.com>