Add future deprecation message in Timelion application (not Timelion chart)

[AlonaNadler]

Currently, we have two places Timelion exists in Kibana, Timelion application and Timelion visualization in Visualize. In 8.0 we want to deprecate Timelion as an application, remove Timelion from the kibana sidebar and continue with Timelion as a visualization in Visualize, to allow more consistent experience and a common location for all kibana charts.

Describe the feature: In Timelion application only (not Timelion chart in Visualize) we will add a deprecation icon and a message indicating the Timelion application will be deprecated in 8.0 and removed from the navigation bar. Timelion is a great way to visualize time series data using expression language and will still be available from Visualize, using Timelion chart, a migration from Timelion sheets to Timelion visualization object will be provided in the future.

cc: @gchaps @elastic/kibana-app

[gchaps]

@AlonaNadler

For the Timelion deprecation notice, how about we use an EUI callout like on this page.

Here is my attempt at keeping the text light, short, and on the positive side.

Timelion is changing

The Timelion application is going away in 8.0. But don't worry!

We're continuing support for Timelion in Visualize, and all your Timeline sheets will be migrated to Timelion visualization objects.

[AlonaNadler]

That will be good :) we need it to appear only on Timelion application, not in Timelion in visualize

[AlonaNadler]

In second thought since this message is not in 7.0 maybe it is too late and we should wait to see how it comes across

[stratoula]

I am closing it as it is a duplicate of this #63012 and has been done