Hue improvements

[robbiet480]

Description:

• Allow disabling of Hue groups
• Allow automatic removal of all Hue entities from emulated_hue
• Don't require a host. Platform will error out if no configuration file is found
• Provide defaults to voluptuous where possible instead of setting defaults in setup_platform

Pull request in home-assistant.github.io with documentation (if applicable): home-assistant/home-assistant.github.io#<home-assistant.github.io PR number goes here>

Example entry for configuration.yaml (if applicable):

light:
  - platform: hue
    allow_in_emulated_hue: false
    allow_hue_groups: false

Checklist:

If user exposed functionality or configuration variables are added/changed:

• Documentation added/updated in home-assistant.github.io

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

• 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.

[mention-bot]

@robbiet480, thanks for your PR! By analyzing the history of the files in this pull request, we identified @balloob, @maddox and @fabaff to be potential reviewers.

[balloob]

Possible to make these two optional when False ?

[robbiet480]

Sure