[UnifiedFieldList] Persist field list sections state in local storage

[jughosta]

Part of #137779

Summary

This PR uses localStorage to persist which list sections user prefers to expand/collapse per app (discover and lens state is saved separately).

Checklist

• Unit or functional tests were updated or added to match the most common scenarios
• This was checked for cross-browser compatibility

[elasticmachine]

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

[davismcphee]

Pulled and tested locally, LGTM!

[stratoula]

Thanx, this works great. Visualizations team changes LGTM

[kibana-ci]

💚 Build Succeeded

• Buildkite Build
• Commit: 6ea5bff

Metrics [docs]

Module Count

Fewer modules leads to a faster build time

id	before	after	diff
unifiedFieldList	83	86	+3

Public APIs missing comments

Total count of every public API that lacks a comment. Target amount is 0. Run node scripts/build_api_docs --plugin [yourplugin] --stats comments for more detailed information.

id	before	after	diff
unifiedFieldList	244	245	+1

Async chunks

Total size of all lazy-loaded chunks that will be downloaded as the user navigates the app

id	before	after	diff
discover	395.9KB	395.9KB	+33.0B
lens	1.3MB	1.3MB	+58.0B
unifiedFieldList	48.3KB	50.6KB	+2.3KB
total			+2.4KB

Page load bundle

Size of the bundles that are downloaded on every page load. Target size is below 100kb

id	before	after	diff
unifiedFieldList	36.5KB	36.5KB	+49.0B

Unknown metric groups

API count

id	before	after	diff
unifiedFieldList	269	270	+1

History

• 💚 Build #98256 succeeded 5dd4019
• 💚 Build #98083 succeeded 62302ce
• 💔 Build #98054 failed 68f8805

To update your PR or re-run it, just comment with:
@elasticmachine merge upstream

cc @jughosta