Remove monitored conditions from syncthru configuration

[nielstron]

Breaking Change:

The monitored_conditions configuration option has been removed. All available monitored conditions will be used by default. Users that have been using the monitored_conditions option need to remove it from the syncthru section in configuration.yaml.

Description:

As noted in this comment on my last PR monitored conditions are to be successively removed from home-assistant. Thus, now it is forbidden to use them anymore.
Removes the option of specifying monitored conditions in the syncthru component.

Pull request with documentation for home-assistant.io (if applicable): home-assistant/home-assistant.io#9825

Example entry for configuration.yaml (if applicable):

sensor:
  - platform: syncthru
    resource: http://my-printer.address
    name: My Awesome Printer

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.

[MartinHjelmare]

Thanks!

Please write the breaking change paragraph so we can copy it directly to the release notes. It should mention what has changed and explain what the user needs to do to cope with the breaking change.

Eg:

The monitored_conditions configuration option has been removed. All available monitored conditions will be used by default. Users that have been using the monitored_conditions option need to remove it from the syncthru section in configuration.yaml.

You can add a link to the adr in the first sentence.

[nielstron]

I have now simply copied your paragraph, including a link. Is it ok like that?

[MartinHjelmare]

Great!

Please rebase on latest dev branch to let the build pass.