Use the visualizeLoader for dashboards

[timroes]

I think we should use the visualize loader to load vizualizations on the dashboard (i.e. the VisualizeEmbeddableFactory).

Currently we expose the loader as kind of an API to load visualizations but don't use it ourselves anywhere. I think using it would make sure, we thoroughly test it, and it will also stay up-to-date with changes we do.

Also we would get a good feeling on what extensions we need to make to the API, that something like dashboards can properly work with it. Last but not least, we could get rid of another part of Angular in the Dashboard, since the visualize loader exposes pure JavaScript.

[bhavyarm]

@timroes do we need to have functional tests for this? Also if I add every visualization to a dashboard and reopen it - is that sufficient testing? Thanks!

[timroes]

@bhavyarm ideally this shouldn't change ANY functionality, since it's just an internal code refactoring. Meaning everything should still work the same as before, and all dashboarding tests should run the same. So this change shouldn't give you any new testing scenarios, if we are missing functional dashboard tests, it would be the same that have already been missing beforehand :-)

[bhavyarm]

Great. Thanks @timroes