Migrate Dashboard directive/model to VueJS #18883

Description:

Changes:

• Migrated the piwik-dashboard directive to Vue.
• Migrated the dashboards-model service to a store.
• Created the ReportingPage.loadPage client side event so reportingpage doesn't have to access an angularjs scope.
• Created the Dashboard.loadDashboard client side event so dashboardObject.js doesn't have to access an angularjs scope.

Review

• [ ] Functional review done
• [ ] Potential edge cases thought about (behavior of the code with strange input, with strange internal state or possible interactions with other Matomo subsystems)
• [ ] Usability review done (is anything maybe unclear or think about anything that would cause people to reach out to support)
• [ ] Security review done
• [ ] Wording review done
• [ ] Code review done
• [ ] Tests were added if useful/possible
• [ ] Reviewed for breaking changes
• [ ] Developer changelog updated if needed
• [ ] Documentation added if needed
• [ ] Existing documentation updated if needed