SHAKE-1: Implement functionality for working with user data.

[vladbidyuk]

Should be implemented the following functionality:

• Read available users from *users_file.csv files and pull them into data structure (memory/cache available during session)
• Write new users to *users_file.csv file

User profile should contain:

• Full name: ex. John Smith
• Group: [ Green, Yellow, Red ]
• Status: [ Available, Unavailable(default) ]
• Face specification. (Currently handled by dlib)

[vladbidyuk]

Containing and management if user data in file is handled. Currently is allow: add, remove and show users in file. Should be done:

• file should contain face specification of user