Updated tox.ini and removed `tests_require` and `setup_requires`

[viniarck]

Description of the change

• Removed tests_require and setup_requires since they'll be deprecated https://github.com/kytos-ng/kytos/issues/229
• Simplified testing commands not to use -- size and --type but instead just use --k <expression> which uses pytest -k that is more flexible to target whichever test selection patterns.
• Parametrized {posargs} on tox.ini to pass down the --k option
• Renegerated requirements/dev.txt accordingly
• Removed unused python setup.py ci command

This change should also make the tests compatible with scrutinizer, it seemed that setup_requires and tests_require weren't fully supported anymore in a particular testing stage.

Examples how to use the --k option

tox

• Let's say you want to target test_update_topology_success_case:

tox -e coverage -- --k test_update_topology_success_case

• Let's say you want to target only unit tests and that's related to filter:

tox -e coverage -- --k 'unit and filter'

Running without tox

Tox calls the underlying python setup.py commands, so if you manage your own venvs you can also run it directly:

• Let's say you want to target test_update_topology_success_case:

python setup.py test --k test_update_topology_success_case 

• Let's say you want to target only unit tests and that's related to filter:

python setup.py test --k 'unit and filter'

[viniarck]

Thanks for reviewing guys