Add service calls for LCN component

[alengwenus]

Description:

Besides the already added LCN platforms, the LCN system offers a number of additional functions which cannot be directly represented by the platforms. In order to use these functionalities as well, this PR adds a bunch of service calls to the LCN component.

The implemented service calls are:

• var_abs: Assign an absolute value to a hardware variable
• var_rel: Shift the value of a hardware variable
• var_reset: Reset the value of a hardware variable
• led: Set lighting mode of hardware LEDs (on, off, blink, flicker)
• lock_regulator: Lock a regulator setpoint
• send_keys: Send hardware keys (which will execute hardware programmed commands)
• lock_keys: Lock a hardware key (so it cannot be activated)
• dyn_text: Send dynamic text to a LCN display
• pck: Send an arbitrary PCK command
• output_abs: Set absolute brightness of an output port with arbitrary transition time
• output_rel: Set relative brightness of an output port with arbitrary transition time
• output_toggle: Toggle an output port with arbitrary transition time
• relays: Switch/Toggle arbitrary hardware relais

Pull request with documentation for home-assistant.io (if applicable): home-assistant/home-assistant.io#9516

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

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 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:

• 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.

[balloob]

I get a feeling here that everything has been made accessible as a service because we can. We should only make things accessible as a service if they are going to be used by users in automations.

[alengwenus]

I get a feeling here that everything has been made accessible as a service because we can. We should only make things accessible as a service if they are going to be used by users in automations.

I just have directed myself to what was also implemented in the OpenHab binding. From the discussions in the forums I get the feeling that people indeed are using these functionalities. It‘s hard to say what people will use. I guess nothing‘s wrong about completeness?