Preserve variables and time range when navigating between dashboards

[dprokop]

Available under preserveDashboardStateWhenNavigating feature toggle.

This is a POC of a functionality that will allow preserving currently selected filters and group by dimensions dashboard variables and time range when navigating between different dashboards. It's an early WIP to gather some opinions.

How it works?

1. Currently selected variable and time range are captured on DashboardScene deactivation and stored in the local storage under a tab-specific key.
2. When new dashboard scene is loaded, we read from local storage and replace the location in the browser with the saved query params, so that when the URL sync is activated, the variables will restore preserved values.
3. When one navigates away from Grafana the preserved filters are cleared.

TODO:

• Deduplicate query params with the same value to avoid duplicate values in scenarios when someone navigates back and forts between the same dashboard (using browser's back button).
• On the target dashboard only apply those query params that match variable names - thi I'm not sure if we need this as this is supposed to work as part of the newDashboardWithFiltersAndGroupBy that guarantees the same name of the filters and group by variable across different dashboards.
• Preserve filters with tab id, so that closing one tab will not cause clearing the filters for other tabs. Or for other tabs not to override filters stored by other tabs.
• Add test coverage

[dprokop]

@torkelo @ashharrison90 - i still need to implement tests, but this should be ready for approach review and testing. Available under preserveDashboardStateWhenNavigating feature toggle.

[torkelo]

Looks good! some minor refactoring that could simplify and reduce the string/url manipulation, and missing tests but otherwise this looks really good.

An interesting thing to discuss with @thanos-karachalios and @Ijin08 would be how users could opt in to this when moving between specific dashboards (ctrl+click or something, or maybe an icon in the dashboard search or dashboard links)

[torkelo]

any reason not using UrlSyncManager.getUrlState(scene) here? (I know it might have more state you don't care about but we can filter that out either before save or when we try to use it)

[ashharrison90]

behaviour-wise looks great 🙌

just a couple of structure suggestions that i think will help make this cleaner

[ashharrison90]

great job on this 👏👏👏

just some minor nits

[torkelo]

Still not sure why we are not using UrlSyncManager.getUrlState(scene) here

[dprokop]

IMO it's better to opt-in for params to sync, rather than removing items from the full state (may include setting, panel edit, view panel id etc...).

[torkelo]

@dprokop but instead of removing state you don't care about just include from & to and all that start with var- , that is basically the same as the code here but much smaller and less complex

[dprokop]

just pushed 👍