Deprecate the current shared customizable dashboard component

Problem to solve

The current customizable_dashboard.vue component in the vue shared directory is heavily tied to Analytics dashboards and cannot easily be used in every context.

As part of our new dashboard framework approach this component will be replaced by a more modular reusable customizable dashboard in Create a new customization component based on t... (#546201).

Proposed solution

Deprecate the shared customizable_dashboard.vue component by moving it and its related files to the analytics dashboard directory.