Create a new wrapper for `requests`.

The wrapper function `request` in module `robottelo.api.client` is intended to
replace the similar wrapper function in `robottelo.api.base`.
Add unit tests for module robottelo.api.client
Add wrappers for more requests functions

Add wrappers for the following `requests` functions:

* head
* get
* post
* put
* patch
* delete

Take logging code and place it in a separate function. Make the logging function
capable of accepting more inputs and make its output nicer to read.
Write tests for module robottelo.api.client

Make tests for all untested code in target module. Fix a bug which was found
while writing tests.
Add new modules to API docs.

Add the following modules to the API docs:

* `robottelo.api.client`
* `tests.test_robottelo_api_client`

Also: fix a bug in `docs/api/tests.robottelo.rst`.
Provide more data to logging functions
Merge pull request #919 from Ichimonji10/requests-wrapper

Make a better `requests` wrapper