[Discover] Evaluate disabling syncing appState to URL

[kertal]

Discover's state is getting more an more complex, syncing the appState to URL can be a huge headache when developing new features, and it's a cause for redundant re-renderings, so it can also impact performance. Furthermore, in edge case scenarios it's possible to run into "The URL for this object is too long, and we can't display it" errors. https://github.com/elastic/kibana/issues/177528

We should therefore evaluate to disable syncing appState changes to URL, aligning the behavior to Dashboard/Lens. Dashboards just takes the URL for initial syncing but every subsequent change isn't synced back, and the AppState part of the URL is removed on initial sync:

To consider:

• We need to be aware that Discover is more used as a data exploration tool, than an editor, so it's more important that refresh and open a new tab works without loosing the state (Additional note, using Ad-hoc data views, then this use case is already broken)
• We might consider warning the user when reloading, in case it would loose state (and we wouldn't have a way to prevent this)

So the upside of this change is

• Aligning URL state behavior to Dashboards/Lens
• No more problems with too long URLs
• Simpler development of Discover state changes

The downsides

• Copy/Paste the URL no longer works, the Share functionality has to be used (Like in other parts of Kibana)
• Reload the browser tab would loose the state, but like Dashboards this could be solved by persisting the most recent state in localStorage/sessionStorage
• Browser history back/forward no longer works for undoing / redoing changes

Since our Share functionality covers the generation of links, it's no regression, however, currently it takes 2 clicks to get to the link. Having a 1 click functionality would prevent this "More clicks" UX regression, one way to do this would e.g. providing a button in the breadcrumb, something @ryankeairns recently suggested:

Or a dedicated icon for this added to our top nav links?

Here's some code how Dashboards is handling it:

https://github.com/elastic/kibana/blob/26389e50140be0188bee7e4fc0307c7c2688122e/src/plugins/dashboard/public/dashboard_app/url/sync_dashboard_url_state.ts#L65

https://github.com/elastic/kibana/blob/6150f76abae664856a976bc230b9e90dbd844621/src/plugins/dashboard/public/dashboard_app/dashboard_app.tsx#L182-L192

[elasticmachine]

Pinging @elastic/kibana-data-discovery (Team:DataDiscovery)