switch from esArchiver to saved objects API for .kibana data in functional tests

[LeeDr]

We currently use esArchiver to load both test data and Kibana data (which are saved objects stored in the .kibana index).
We should switch to loading the Kibana data using the saved object API https://www.elastic.co/guide/en/kibana/master/saved-objects-api.html

1. We advise users NOT to write directly to the .kibana index
   "Do not write documents directly to the .kibana index. When you write directly to the .kibana index, the data becomes corrupted and permanently breaks future Kibana versions."

2. The saved object API is the recommended way.

3. When we use esArchiver to load data, it removes everything else first (except the default space). But using the Saved Object API we could potentially choose to add objects to the existing objects.

Back when most of the functional tests were written, we didn't support exporting and importing everything in the .kibana index. I'm not 100% sure if everything is now supported but I think it should be.

The steps to switch from using esArchiver to the SO API would probably be;

1. Add a line in each test (or index file) where esArchiver is loading a .kibana indexthat exports saved objects
2. run the tests to get all the exported files
3. change the tests to
   1. remove the original esArchiver load
   2. add a new step to clear other saved objects out? We need to figure this part out. WARNING: This probably won't come up on the first test. Ideally every test would wipe the existing saved objects and import the set the tests need.
   3. change the SO export to the SO import
4. run the tests to verify they pass

[elasticmachine]

Pinging @elastic/kibana-qa (Team:QA)

[wayneseymour]

Up next: Import the exported data and see if the tests pass, might have to data munge.
After: Investigate hijacking the es_archiver.load fn to export and persist the data.

[wayneseymour]

Ok, so the first and second pr's are up.
The second pr stands on top of the first and it will take longer to turn around as it's for every test in disover.

[rudolf]

Back when most of the functional tests were written, we didn't support exporting and importing everything in the .kibana index. I'm not 100% sure if everything is now supported but I think it should be.

We've added all the required building blocks in 7.12 (#90178), but it might take some time for plugins to adopt it and enable their saved objects to be exported.

Some plugins might also choose to use the onExport transform (#87807) to change saved objects when they're exported. These plugins might have to manually edit the ndjson before it can be imported for a test. E.g. alerting will remove all credentials from alerts when they're exported, but these kinds of edge cases can probably continue to use esArchiver.

[rudolf]

Implemented in #92526