Refactor event subscription

[helto4real]

Breaking change

This PR introduces some breaking changes. The rationale for these changes is to allow more granular subscriptions to events and remove default subscriptions to all events for users of IHomeAssistantConnection.

Most users does not use the HassClient and should not be affected by this change.

IHomeAssistantConnection

• ProcessHomeAssistantEventsAsync method no longer defaults to subscribing to all event changes. That logic is moved the new method SubscribeToHomeAssistantEventsAsync that returns the IObservable<HassEvent> instead of make it available as a property on the interface itself.
• OnHomeAssistantEvent is removed and replaced by the method SubscribeToHomeAssistantEventsAsync

ServiceCollectionExtensions

• IObservable<HassEvent> is no longer injectable through DI due to internal design change providing it through the SubscribeToHomeAssistantEventsAsync on the IHomeAsstantConnection interface instead.

Proposed change

This PR refactors how event subscriptions work. Now it does not automatically subscribe to all events from the HomeAssistantConnection. The runtime and HassModel do add these subscriptions automatically. The function now also supports subscribing to specific avents.

Type of change

• Dependency upgrade
• Bugfix (non-breaking change which fixes an issue)
• 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][dev-checklist]
• The code compiles without warnings (code quality chek)
• 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

[helto4real]

Still have a few tests I want to add but we can discuss the overall design first. I also have the nested task thing to take care of.
[edit, all tests and refactorings are now included and the PR is ready for review]

[codecov]

Codecov Report

Patch coverage: 93.47% and project coverage change: +0.04 🎉

Comparison is base (72a0ed4) 80.70% compared to head (9c32ee9) 80.74%.

❗ Current head 9c32ee9 differs from pull request most recent head 5dc6874. Consider uploading reports for the commit 5dc6874 to get more accurate results

Additional details and impacted files

@@            Coverage Diff             @@
##              dev     #868      +/-   ##
==========================================
+ Coverage   80.70%   80.74%   +0.04%     
==========================================
  Files         167      168       +1     
  Lines        4229     4244      +15     
  Branches      423      423              
==========================================
+ Hits         3413     3427      +14     
  Misses        642      642              
- Partials      174      175       +1     

Flag	Coverage Δ
unittests	80.74% <93.47%> (+0.04%)	⬆️

Flags with carried forward coverage won't be shown. Click here to find out more.

Impacted Files	Coverage Δ
...nt/Common/Extensions/ServiceCollectionExtension.cs	97.56% <ø> (-0.06%)	⬇️
...mon.HassClient/Internal/HomeAssistantConnection.cs	87.21% <91.89%> (+1.15%)	⬆️
...NetDaemon.HassClient/Internal/Helpers/AsyncLazy.cs	100.00% <100.00%> (ø)
...tDaemon.HassClient/Internal/HomeAssistantRunner.cs	88.42% <100.00%> (ø)
...el/NetDeamon.HassModel/Internal/EntityAreaCache.cs	75.00% <100.00%> (-2.28%)	⬇️
...l/NetDeamon.HassModel/Internal/EntityStateCache.cs	87.17% <100.00%> (ø)
...time/NetDaemon.Runtime/Internal/AppStateManager.cs	87.14% <100.00%> (+0.37%)	⬆️

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[helto4real]

I missed a few spots in the tests and also fixed old tests that had the same problem. I will merge this now. Thanks for the review @FrankBakkerNl