Migrate vacuum_mode switch from legacy to modern template format (#53)

* Migrate vacuum_mode switch from legacy to modern template format

The legacy `platform: template` switch format is deprecated.
This moves the vacuum_mode switch to the modern template integration
format in templates.yaml and removes the now-empty switches.yaml file.

Entity ID changes from switch.vacuum_mode to switch.vacuum_mode
(same ID since unique_id is now set).

* Add templates.yaml coverage for all template entity types in README script

The update-readme.py script now properly handles sensors, binary_sensors,
and switches defined in templates.yaml, not just the legacy YAML files.

* Fix update-readme.py to use main branch instead of master

Also regenerate README.md with updated entity links that now correctly
reference templates.yaml for template-based sensors, binary_sensors,
and switches.

* Fix update-readme.py to find entities in modern template format

The script now searches for both legacy format (entity_name:) and
modern template format (unique_id: entity_name), allowing it to
properly link to entities defined in templates.yaml.

* Fix misleading comment in permalink_entity function

* Add case-insensitive name matching to find template entities

The script now also searches for entities by their friendly name
(e.g., "name: activity in living room" for entity_id
"binary_sensor.activity_in_living_room"). This finds more entities
defined in templates.yaml without unique_id.

Note: Some entities still can't be found due to naming mismatches
(e.g., entity_id has "activity_in_living_room" but template name
is "Activity in the living room" with extra "the"). These would
need unique_id added to templates.yaml to be found reliably.

Author: basnijholt