[Files] Add file upload to file picker

[jloleysens]

Summary

See original comment: #143111 (comment)

Screen.Recording.2022-10-25.at.17.48.37.mov

Notes

• Also adds fix to avoid collapsing the files$ observable on error
• Hide the pagination controls when there are no files (added a small test)
• Update debounce so that loader always shows

Checklist

Delete any items that are not applicable to this PR.

• Any text added follows EUI's writing guidelines, uses sentence case text and includes i18n support
• Unit or functional tests were updated or added to match the most common scenarios

[elasticmachine]

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

[kibana-ci]

💚 Build Succeeded

• Buildkite Build
• Commit: e175ac1

Metrics [docs]

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
files	18	19	+1

Async chunks

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

id	before	after	diff
files	25.8KB	27.2KB	+1.3KB

Public APIs missing exports

Total count of every type that is part of your API that should be exported but is not. This will cause broken links in the API documentation system. Target amount is 0. Run node scripts/build_api_docs --plugin [yourplugin] --stats exports for more detailed information.

id	before	after	diff
files	2	3	+1

Unknown metric groups

API count

id	before	after	diff
files	271	275	+4

History

• 💚 Build #82553 succeeded d6500a3

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@elasticmachine merge upstream

[Dosant]

tested, works well 👍