COOPR-579: Move authentication service to the common repo

@sreevatsanraman and @poornachandra , please take a look to the first commit. In the ```cdap-common``` sub-module there are a lot dependencies on the ```cdap-api```, so, I'm not sure, what I need to do with these classes from the ```cdap-api```. I added ```cdap-api``` as dependency, but I understand, that it should be removed from this project, to avoid dependencies on the cask repo. Should I also create some separate sub-module in the common repo for these classes from the ```cdap-api```? Please note, that I also moved a lot of classes from the ```cdap-common```, which are used in the security module.