Implement the Auth interface, with JWT and service implementations.
* Update Auth Interface
* Define Auth Service Implementation
* Support Service Auth
* Add Auth Service Proto
* Remove erronious files
* Implement Auth Service Package
* Update Auth Interface
* Update Auth Interface. Add Validate, remove Add/Remove roles
* Make Revoke interface more explicit
* Refactor serializing and deserializing service accounts
* Fix srv name & update interface to be more explicit
* Require jwt public key for auth
* Rename Variables (Resource.ID => Resource.Name & ServiceAccount => Account)
* Implement JWT Auth Package
* Remove parent, add ID
* Update auth imports to v2. Add String() to auth interface
The original signature accept a boolean, and it feel like a little
verbose, since when people pass in this option, he/she always want to
pass a `true`.
Now if input `wg` is nil, it has same effect as passing `true` in
original code. Furthermore, if user want's finer grained control during
shutdown, one can pass in a predefined `wg`, so that server will wait
against it during shutdown.
