Added insteonplm device_override multiple capabilities

[teharris1]

Description:

Some older devices do not repsond to auto discovery correctly. The insteonplm device_override configuration setting allows for these devices to be configured with the correct capabilities. This change allows for multiple capabilities to be added to a single device to better support these items.

Related issue (if applicable): fixes #

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):

insteon_plm:
  port: /dev/insteon
  device_override:
    - address: '2c3832'
      platform: 
        - light
        - dimmable

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]

@teharris1, thanks for your PR! By analyzing the history of the files in this pull request, we identified @balloob, @nugget and @fabaff to be potential reviewers.