Remove metadata.json and update application readme.
Remove metadata.json and update application readme.

* Metadata.json can be generated with the rake tasks.
* Use 'metadata[cookbook]' and 'metadata_all' to generate .json.
* Application readme needed a few more clarification points.

tfly-cookbooks/logrotate,strebitz/logrotate,sh9189/logrotate,evertrue/logrotate,cookbooks/oc-logrotate,sh9189/logrotate,Altiscale/logrotate,stevendanna/logrotate,tfly-cookbooks/logrotate,gleamicus/logrotate,strebitz/logrotate,evertrue/logrotate,stevendanna/logrotate,Altiscale/logrotate