[avmfritz] Add support for groups of blinds

[cweitkamp]

• Added support for groups of blinds

Signed-off-by: Christoph Weitkamp github@christophweitkamp.de

[Copilot]

Pull Request Overview

This PR adds support for groups of blinds in the avmfritz binding, enabling control of roller shutters/blinds that are grouped together in the FRITZ!Box system.

Key Changes:

• Added new FRITZ_GROUP_BLINDS thing type for blind groups
• Moved LevelControlModel from DeviceModel to AVMFritzBaseModel to enable sharing between devices and groups
• Updated handler logic to support blind control for both individual devices and groups

Reviewed Changes

Copilot reviewed 10 out of 10 changed files in this pull request and generated 1 comment.

Show a summary per file

File	Description
AVMFritzBindingConstants.java	Added constant and ThingTypeUID for the new blinds group type
AVMFritzBaseModel.java	Moved levelControlModel field and its getters/setters from DeviceModel to base class
DeviceModel.java	Removed levelControlModel field as it was moved to parent class
AVMFritzBaseBridgeHandler.java	Added logic to identify blind groups when discovering devices
AVMFritzBaseThingHandler.java	Updated handler to process blind updates for both devices and groups
thing-types.xml	Added XML configuration for the new blinds group thing type
avmfritz.properties	Added i18n labels for blinds group
README.md	Updated documentation to describe the new blinds group support
AVMFritzDeviceListModelTest.java	Added test data and validation test for blinds group
AVMFritzDiscoveryServiceOSGiTest.java	Updated test to reflect new supported thing type count

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[lsiepel]

Thanks, except for the test failing and the typo discovered by copilot i have no additional comments.