Refractor the existing controllers

[HeeManSu]

The TODO task has been added in several places. Complete them and refactor the other controllers for any potential improvements.

[khareyash05]

On it! Kindly assign me this

[viferga]

This is almost done but there's something remaining, all the lines containing this:

// TODO: Isn't this available inside protocol package? We MUST reuse it

This may be common and we either have to find one existing type/interface in the protocol or export the one in the faas into the protocol.

Maybe we can close this issue and create a new one only for the interface thing. What do you think @HeeManSu ?