[Cleanup] Modify `RemoteScrollableHitSource` and `RemoteRequestBuilders` to stop using the `Version` class

[msfroh]

Is your feature request related to a problem? Please describe

See the parent issue for details

Describe the solution you'd like

We have a number of calls to LegacyESVersion.fromString() that exist to reference very old Elasticsearch versions. In many cases, it's just for testing and we should be able to use OpenSearch versions instead.

One significant exception is related to RemoteScrollableHitSource, which allows reindexing from remote clusters.

My preference would be to either say:

1. OpenSearch 3.x doesn't support reindexing from Elasticsearch clusters. (Maybe controversial from a usability standpoint.)
2. The RemoteRequestBuilders class can customize behavior to talk to specific versions of Elasticsearch, but shouldn't do it using the global Version class. It can define its own versioning class that supports extended backward compatibility.

I think the second option is safer and more user-friendly, so that's what I'm proposing in this class.

Related component

Other

Describe alternatives you've considered

No response

Additional context

No response

[HyunsangHan]

May I work on this?

[andrross]

@HyunsangHan Yes! I've assigned the issue to you.

[HyunsangHan]

@andrross @msfroh I've just submitted a PR! #18457