feat: Build dashboards with Display Builder instead of Layout Builder

Problem/Motivation

Web Dashboard needs an initial module import. Dashboards should be config entities built with Display Builder rather than Layout Builder, so editors can compose personalized dashboards from items such as charts and views.

Steps to reproduce

N/A — this is the initial import of the module, not a bug.

Proposed resolution

• Add the Web Dashboard module: dashboards as config entities built with Display Builder.
• Support personalization and dashboard items (charts, views).
• Ship submodules plus kernel and functional test coverage.

Remaining tasks

• ✅ File an issue about this project
• ❌ Addition/Change/Update/Fix to this project
• ❌ Testing to ensure no regression
• ➖ Automated unit/functional testing coverage
• ➖ Developer Documentation support on feature change/addition
• ➖ User Guide Documentation support on feature change/addition
• ➖ UX/UI designer responsibilities
• ➖ Accessibility and Readability
• ❌ Reviewed by a human
• ❌ Code review by maintainers
• ❌ Full testing and approval
• ❌ Credit contributors
• ❌ Review with the product owner
• ❌ Update Release Notes
• ❌ Release

User interface changes

• N/A

API changes

• N/A

Data model changes

• N/A

Release notes snippet

• N/A