[Reporting] CSV features from Dashboard: add "Generate CSV" option, deprecate "Download CSV" option

[tsullivan]

Kibana version:
8.4.+

Elasticsearch version:

Server OS version:

Browser version:

Browser OS version:

Original install method (e.g. download page, yum, from source, etc.):

Describe the change:
Users have described performance issues with the "Download CSV" option in Dashboard. The workaround is to navigate to Discover and use the "Generate CSV" option to create a report of a saved search.

Background
The reason for the performance problems are due to using Kibana as a bridge between scan-and-scroll data from Elasticsearch and the end-user's browser. Certain things specific to "Download CSV' create weak links in the chain:

• Elasticsearch may need a lot of time preparing a long search context due to a large number of results
• A proxy can be in place that either forwards for Elasticsearch or forwards for Kibana. These proxies could time out requests that have high response latency.

Proposal
There already is a config setting to show/hide the "Download CSV" option: xpack.reporting.csv.enablePanelActionDownload. I propose 2 things:

• Add a "Generate CSV" option to the share menu of the saved search dashboard panel, and create an Kibana Application Privilege for admins to allow users to use that option.
• Log that usage of the xpack.reporting.csv.enablePanelActionDownload option is deprecated due to performance reasons.

This change will make the "workaround" for the performance problem a front-and-center solution in the user experience.

[elasticmachine]

Pinging @elastic/kibana-app-services (Team:AppServicesUx)

[tsullivan]

Closing this for a simpler proposal. Looks like there is little interest in deprecating "Download CSV", and we haven't seen a true general trend in performance or issues with it.