Fix snapshot repository definitions

[swallez]

In the snapshot namespace we only have a (partial) definition of the S3 repository. This PR defines the settings for all repository implementations and groups them in a @non_exhaustive union (plugins can define new snapshot repositories).

Found in elastic/elasticsearch-java#207

[sethmlarson]

Thanks for this! Here's some comments and questions:

[sethmlarson]

Should this be string[]?

[sethmlarson]

Missing the client property

[github-actions]

Following you can find the validation results for the APIs you have changed.

API	Status	Request	Response
snapshot.cleanup_repository	🟢	3/3	3/3
snapshot.clone	🟢	5/5	5/5
snapshot.create_repository	🟢	26/26	26/26
snapshot.create	🟢	26/26	26/26
snapshot.delete_repository	🟢	10/10	10/10
snapshot.delete	🟢	20/20	20/20
snapshot.get_repository	🟢	19/19	19/19
snapshot.get	🟢	13/13	13/13
snapshot.repository_analyze	🟠	Missing type	Missing type
snapshot.restore	🟢	5/5	5/5
snapshot.status	🟢	2/2	2/2
snapshot.verify_repository	🟢	2/2	2/2

You can validate these APIs yourself by using the make validate target.

[swallez]

I addressed your comments. Can you review the latest changes?

[sethmlarson]

This looks good, I only had one question:

[sethmlarson]

Is there a reason we switched the @aliases and the non-alias property name from the previous types?

[swallez]

This is because some recordings use read_only but the setting name in the ES code is readonly. I couldn't find though in the ES code where that read_only would be accepted.

[steffenvan]

Hi, I was wondering what the timeline is to merge this PR?

[pquentin]

Should we close this since #2255 from @JoshMock was merged instead? Or is there still work to do?

[JoshMock]

@pquentin Yes, I believe we can close this.