Pass resourceType instead of resourceIndex to resourceSharingClient

[cwperks]

Description

This PR is related to the changes in opensearch-project/security#5713 to support multiple resource types in the same index. There's a small change in all ResourceSharingClient methods to accept type in the place of index.

resource type <-> resource index is a many-to-one relationship (think dashboards saved objects where multiple saved object types are in the same index).

On another note, ResourceSharingClient is used in instances where a mechanism doesn't currently exist as in parent<->child relationships (like a detector and results where all results are associated with a detector). Security is working on a mechanism to support this natively to obviate the need for ResourceSharingClient and instead abstract all the logic behind-the-scenes to the security plugin.

Check List

• New functionality includes testing.
• New functionality has been documented.
• API changes companion pull request created.
• Commits are signed per the DCO using --signoff.
• Public documentation issue/PR created.

By submitting this pull request, I confirm that my contribution is made under the terms of the Apache 2.0 license.
For more information on following Developer Certificate of Origin and signing off your commits, please check here.