[FEATURE] Create infrastructure to test E2E flow for multiple datasource feature

[derek-ho]

Is your feature request related to a problem?

Today, there is no way to test the multiple datasources feature. The existing tests use a dummy endpoint (opensearch.org), with no ability to have any CRUD operations done on it. OSD core itself should be able to test validation/creation of a real endpoint, and any plugins onboarding onto this feature should also be able to test this same real-world use case.

What solution would you like?

Infrastructure to spin up a real external datasource (opensearch for now). For example, running on a different port within the same github runner so FTR tests can be run that can add/remove/perform CRUD operations on that external datasource.

What alternatives have you considered?

None

Do you have any additional context?

None

[derek-ho]

Completed with: #1146