Server support for protocols

[joamag]

Description

This is a follow-up to #26 - because it was closed to allow major master branch refactoring.

Achievements

• Echo server working with both netius (compat and native) and asyncio (via compat COMPAT=1 ASYNCIO=1)
• Review Server support for protocols #26 code to check for strategy that was applied there and do a proper follow-up
• Decide on pylint - so we want do go forward with it or not - if we want add it to GitHub Actions
• Review https://github.com/hivesolutions/netius/blob/master/src/netius/examples/upnp.py and make sure it works now that SSDPClient is protocol-driven
• Create a Markdown table with all the clients and servers that have already been migrated to the new Protocols strategy - put the table in https://github.com/hivesolutions/netius/blob/master/doc/compat.md
• Make the HTTP server work with COMPAT mode
• Document the protocol support in https://github.com/hivesolutions/netius/blob/master/doc/compat.md
• Add unit test mocks and support to guarantee that minimalist protocol testing is done - Make use of it to cover echo and HTTP servers and clients
• Add more pedantic type hinting support (.pyi files) to reduce the error rate of the code

References

• Related to Protocols support 🚀 #23