Load requirements and dependencies from manifests. Fallback to current REQUIREMENTS and DEPENDENCIES

[rohankapoorcom]

Breaking Change:

To developers: Setup entity platform will set up its component now despite DEPENDENCIES.

For example, if you have an integration smart_home, it has some connection management code in smart_home/__init__.py and it provides light and sensor. In smart_home/light.py, it has DEPENDENCIES=['smart_home'], it will use smart_home/__init__.py to manage its connection. So when light domain set up its platform, it will load smart_home/light.py, then as the dependencies's require, smart_home/__init__.py will be load and its async_setup() method will be called. The process is not changed, however, such dependencies pointed to its own component is not required anymore, because we will load and set up the smart_home component as long as you set up smart_home/light.py no matter DEPENDENCIES exists or not.

On the other hand, let's say smart_home/sensor.py does not rely on smart_home/__init__.py, so there is no DEPENDENCIES in smart_home/sensor.py. After this PR, the behavior changed, we will load and set up the smart_home component as long as you set up smart_home/sensor.py

Such behavior change may break your component. As far as I know, following component will have problem after this PR merged

• demo
• google
• telegram

Description:

Load requirements and dependencies from manifests (if present). If not, fallback to the current approach of reading REQUIREMENTS and DEPENDENCIES from the module attribute.

Related issue (if applicable): relates to #22700

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 the code does not interact with devices:

• Tests have been added to verify that the new code works.

[rohankapoorcom]

Will fix in the evening. Thanks for the feedback.

[awarecan]

Add tests/common::mock_entity_platform() method, can be use to replace loader.set_component

-        loader.set_component(self.hass, 'test_domain.platform', platform)
+        mock_entity_platform(self.hass, 'test_domain.platform', platform)

[awarecan]

@balloob I have to go, won't check in code for this PR today. Feel free to change whatever need

[balloob]

I think I got last one fixed. When it's green, let's merge

[awarecan]

"fixed" google tts.

Now load google tts platform will setup google component as well. I add a shortcut in google component to allow test pass. However it may break the google component, e.g. google calendar and tts cannot configured together. We need reorg google tts to a separate folder, such as google_tts. If we want to merge several google_* component then we need do it right, not a simple git mv.