Add base support for sub entries (#23160)

* Add base support for sub entries

* add demo types

* fix translations

* Use sub entry name when deleting

* Update show-dialog-sub-config-flow.ts

* adjust for multiple sub types

* WIP, not functional

* add subentry_type

* rename to supported_subentry_types

* config_subentries -> config_entries_subentries

* Add localized sub flow title

* use Record

* rename

* more rename

demo/src/stubs/config_entries.ts

@@ -11,6 +11,7 @@ export const mockConfigEntries = (hass: MockHomeAssistant) => {
     supports_remove_device: false,
     supports_unload: true,
     supports_reconfigure: true,
+    supported_subentry_types: {},
     pref_disable_new_entities: false,
     pref_disable_polling: false,
     disabled_by: null,