Switch to config_flow for Environment Canada (#57127)

* Add config_flow to Environment Canada

* Add unique_id

* Remove erroneous directory.

* Tests working!!

* Add back setup.

* First cut of import.

* Temp

* Tweak names.

* Import config.yaml.

* Clean up imports.

* Import working! Some refactor to clean it up.

* Add import test.

* Small optimization.

* Fix comments from code review.

* Remove CONF_NAME and config_flow for it.

* Fixup strings to match new config_flow.

* Fixes for comments from last review.

* Update tests to match new import code.

* Clean up use of CONF_TITLE; fix lint error on push.

* Phew. More cleanup on import. Really streamlined now!

* Update tests.

* Fix lint error.

* Fix lint error, try 2.

* Revert unique_id to use location as part of ID.

* Fix code review comments.

* Fix review comments.