Include pinned testing dependencies on setup.py to extra_requires dev to be reused by NApps

[viniarck]

There's opportunity to also share and install similar python testing dependencies that NApps from kytos-ng org will need anyway, and currently end up being duplicated on NApps dev.in and dev.txt files. kytos already partly delivers reusable testing dependencies, but we can also include other ones that haven't been added yet like pytst-asyncio, black and so on. This is also related to enhancements mentioned on #338

If NApps that don't belong to Kytos-ng org don't want these dependencies, then they shouldn't install in dev mode, or alternatively they can overwrite it whenever needed.

Example of duplicated testing deps maintainability effort:

napps/amlight/coloring/requirements/dev.txt
210:pytest-asyncio==0.18.3

napps/kytos/maintenance/requirements/dev.txt
210:pytest-asyncio==0.18.3

napps/kytos/of_core/requirements/dev.txt
191:pytest-asyncio==0.18.3

napps/kytos/of_lldp/requirements/dev.txt
209:pytest-asyncio==0.18.3

napps/kytos/topology/requirements/dev.txt
198:pytest-asyncio==0.18.3

napps/kytos/mef_eline/requirements/dev.txt
279:pytest-asyncio==0.18.3

napps/amlight/sdntrace_cp/requirements/dev.txt
223:pytest-asyncio==0.18.3

napps/kytos/of_core/src/kytos/requirements/dev.txt
253:pytest-asyncio==0.18.3

napps/amlight/flow_stats/requirements/dev.txt
214:pytest-asyncio==0.18.3

napps/kytos/pathfinder/requirements/dev.txt
200:pytest-asyncio==0.18.3

napps/amlight/sdntrace/requirements/dev.txt
217:pytest-asyncio==0.18.3

napps/amlight/noviflow/requirements/dev.txt
202:pytest-asyncio==0.18.3

napps/kytos/flow_manager/requirements/dev.txt
204:pytest-asyncio==0.18.3