Add Plum Lightpad config flow

[prystupa]

Proposed change

This PR makes it possible for Plum Lightpad integration to be configured via config flow from UI and/or from existing configuration in configuration.yaml.
This PR also exposes Plum dimmers and glow rings as devices, so that they can be manipulated in automations.

Type of change

• Dependency upgrade
• Bugfix (non-breaking change which fixes an issue)
• New integration (thank you!)
• New feature (which adds functionality to an existing integration)
• Breaking change (fix/feature causing existing functionality to break)
• Code quality improvements to existing code or addition of tests

Additional information

• This PR fixes or closes issue: fixes #
• This PR is related to issue:
• Link to documentation pull request:

Checklist

• The code change is tested and works locally.
• Local tests pass. Your PR cannot be merged unless tests pass
• There is no commented out code in this PR.
• I have followed the development checklist
• The code has been formatted using Black (black --fast homeassistant tests)
• Tests have been added to verify that the new code works.

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

• Documentation added/updated for www.home-assistant.io

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

• The manifest file has all fields filled out correctly.
  Updated and included derived files by running: python3 -m script.hassfest.
• New or updated dependencies have been added to requirements_all.txt.
  Updated by running python3 -m script.gen_requirements_all.
• Untested files have been added to .coveragerc.

The integration reached or maintains the following Integration Quality Scale:

• No score or internal
• 🥈 Silver
• 🥇 Gold
• 🏆 Platinum

[probot-home-assistant]

Hey there @ColinHarrington, mind taking a look at this pull request as its been labeled with a integration (plum_lightpad) you are listed as a codeowner for? Thanks!
_{^{(message by CodeOwnersMention)}}

[ColinHarrington]

Thank you for the PR! Looks like the way you did this handles configuration.yaml and config flow.
I appreciate adding types where applicable.

I had a few things to address:

• The cleanup function/shutdown hook
• potential naming questions

[balloob]

Looks great. Ok to merge when last comments addressed!

[ColinHarrington]

It's shaping up well. I have a few requested changes/clarifications.

I'd also like to confirm it's working with actual devices first before merging.

[prystupa]

It's shaping up well. I have a few requested changes/clarifications.

I'd also like to confirm it's working with actual devices first before merging.

Yes, I have tested this code with real devices at my home.

[ColinHarrington]

Looks good! Thank you for going back and forth on the PR!

[MartinHjelmare]

Please address the comments in a new PR.

Tests were not added for the config flow in this PR. We require 100% coverage for the config flow module. Run the scaffold script to generate test example code.

[frenck]

The documentation for this PR is missing, or am I looking incorrect?

[prystupa]

The documentation for this PR is missing, or am I looking incorrect?

Documentation update PR added: home-assistant/home-assistant.io#13869

[prystupa]

The documentation for this PR is missing, or am I looking incorrect?

Documented here: home-assistant/home-assistant.io#13870