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

Load requirements and dependencies from manifests. Fallback to current `REQUIREMENTS` and `DEPENDENCIES` (#22717)

* Load dependencies from manifests. Fallback to current DEPENDENCIES

* Fix typing

* Ignore typing correctly

* Split out dependency processing to a new method

* Fix tests

* Only pull from manifest if dependencies is non empty

* Inline temporary function

* Fix light tests [skip ci]

* Fix tests/common

* Fix some mqtt tests [skip ci]

* Fix tests and component manifests which have only one platform

* Fix rflink tests

* Fix more tests and manifests

* Readability over shorthand format

* Fix demo/notify tests

* Load dependencies from manifests. Fallback to current DEPENDENCIES

* Load requirements from manifests. Fallback to current REQUIREMENTS

* Fix typing

* Ignore typing correctly

* Split out dependency processing to a new method

* Only pull from manifest if dependencies is non empty

* Inline temporary function

* Fix tests and component manifests which have only one platform

* Fix rflink tests

* Readability over shorthand format

* Clean up requirements

* Use integration to resolve deps/reqs

* Lint

* Lint

* revert a change

* Revert a test change

* Fix types

* Fix types

* Add back cache for load component

* Fix test_component_not_found

* Move light.test and device_tracker.test into test package instead with manifest to fix tests

* Fix broken device_tracker tests

* Add docstrings to __init__

* Fix all of the light tests that I broke earlier

* Embed the test.switch platform to fix other tests

* Embed and fix the test.imagimage_processing platform

* Fix tests for nx584

* Add dependencies from platform file's DEPENDENCIES

* Try to setup component when entity_platform is setting up

Fix tests in helpers folder

* Rewrite test_setup

* Simplify

* Lint

* Disable demo component if running in test

Temp workaround to unblock CI tests

* Skip demo tests

* Fix config entry test

* Fix repeat test

* Clarify doc

* One extra guard

* Fix import

* Lint

* Workaround google tts