Update vizio component to prepare for config flow and zeroconf support

[raman325]

Description:

No functional changes

I am planning to add config flow support and zeroconf support for the vizio component. In order to prepare for this, and to make the future PR simpler to review, I upgraded to the latest version of pyvizio, moved constants to const.py, and moved things related to schema validation to __init__.py. While I was in there, I added support for the icon property and changed the function call that the component uses to validate that the component is properly configured.

Checklist:

• The code change is tested and works locally.
• Local tests pass with tox. Your PR cannot be merged unless tests pass
• There is no commented out code in this PR.
• I have followed the development checklist

If the code communicates with devices, web services, or third-party tools:

• The manifest file has all fields filled out correctly. Update and include derived files by running python3 -m script.hassfest.
• New or updated dependencies have been added to requirements_all.txt by running python3 -m script.gen_requirements_all.
• Untested files have been added to .coveragerc.

[MartinHjelmare]

Looks good!

[raman325]

I think the tests need to be re-ran if the failure is a concern