Add LCN switch platform

[alengwenus]

Description:

The LCN switch platform is added. The implementation follows the already merged LCN light platform.

Related issue (if applicable):

Pull request in home-assistant.io with documentation (if applicable): home-assistant/home-assistant.io#8223

Example entry for configuration.yaml (if applicable):

lcn:
  connections:
    - name: myhome
      host: 192.168.2.41
      port: 4114
      username: !secret lcn_username
      password: !secret lcn_password

  switches:
    - name: Sprinkler switch
      address: myhome.0.7
      output: relay1

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.

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

• Documentation added/updated in home-assistant.io

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

• New dependencies have been added to the REQUIREMENTS variable (example).
• New dependencies are only imported inside functions that use them (example).
• New or updated dependencies have been added to requirements_all.txt by running script/gen_requirements_all.py.
• New files were added to .coveragerc.

[MartinHjelmare]

Great!

[MartinHjelmare]

Great!