Feature: Property Value Preset

[nielslyngsoe]

Property Value Presets
A new extension point which bring the ability to provide or alter the preset value for a property.
Fixes #17212

Contains:

• Implementation for Block Workspace, Content Detail Workspace.
• New Extension Point propertyValuePreset which takes an API, which implements the method processValue
• PropertyValuePresetBuilder controller (both basic and variant version available) used to build a preset as part of the model scaffolding in a workspace.
• A few updates to how Content Structure Manager and alike works.
• A few updates to how Data Manager and alike works (see PR which is part of this as well: Fix #18431 #18445)
• Preset for Toggle Property Editor.
• Preset for slider Property Editor Preset.
• Preset for MarkDown Property Editor Preset.

Part of a later PR:

• Make sure this works with Conditions. (Ability to know when all conditions are resolved, not necessary permitting.)
• Ideally also implementation for Data-Types Workspace.

Test notes:

Test for invariant and variant Documents.
Test for invariant and variant Blocks.
Test with Blueprints?

[umbracocommunity]

This pull request has been mentioned on Umbraco community forum. There might be relevant details there:

https://forum.umbraco.com/t/defining-a-default-value-for-a-custom-property-editor-triggers-unsaved-changes-on-new-documents/1838/2