Add schema for cc_chef module (#375)

Create a schema object for the chef module and validate this schema in the handle function of the module.

Some of the config keys description, so I tried looking at the code and chef documentation to provide an information to the user. However, I don't know if I have the best description for all fields. For example, for the key show_time I could not find an accurate description of what it did, so I used what was in our code base to infer what it should do.

LP: #1858888

Author: lucasmoura