UPnP port mapping component

[robbiet480]

Description: This adds a new UPnP component which will automagically port map your Home Assistant instance. It requires miniupnpc to be installed.

Example entry for configuration.yaml (if applicable):

upnp:

Checklist:

If code communicates with devices:

• Local tests with tox run successfully. Your PR cannot be merged unless tests pass
• New dependencies have been added to the REQUIREMENTS variable (example).
• New dependencies are only imported inside functions that use them (example).
• New dependencies have been added to requirements_all.txt by running script/gen_requirements_all.py.
• New files were added to .coveragerc.

If the code does not interact with devices:

• Local tests with tox run successfully. Your PR cannot be merged unless tests pass
• Tests have been added to verify that the new code works.

[balloob]

You need a REQUIREMENTS = for miniupnpc