[BUG] Dashboards index name has been changed, breaks backward compatibility with existing clusters

[hsiang9431-amzn]

Describe the bug
Kibana used to use .kibana* indices in ES cluster, while this behavior is altered after open search name change.
Instead of original .kibana* indices, it uses .opensearch_dashboards* indices.

This behavior change causes opensearch dashboards fail to startup if security policy is enforced in the backend cluster.

To Reproduce

1. Start an opensearch cluster with security plugin
2. start OpenSearch Dashboards, it fails due to insufficient permission
3. check opensearch log output, find error as followed:

[2021-04-29T21:34:40,741][INFO ][c.a.o.s.p.PrivilegesEvaluator] [smoketestnode] No permissions for [indices:admin/get]
[2021-04-29T21:34:43,253][INFO ][c.a.o.s.p.PrivilegesEvaluator] [smoketestnode] No index-level perm match for User [name=kibanaserver, backend_roles=[], requestedTenant=null] Resolved [aliases=[], allIndices=[.opensearch_dashboards], types=[*], originalRequested=[.opensearch_dashboards], remoteIndices=[]] [Action [indices:admin/get]] [RolesChecked [own_index, kibana_server]]
[2021-04-29T21:34:43,256][INFO ][c.a.o.s.p.PrivilegesEvaluator] [smoketestnode] No permissions for [indices:admin/get]
[2021-04-29T21:34:45,766][INFO ][c.a.o.s.p.PrivilegesEvaluator] [smoketestnode] No index-level perm match for User [name=kibanaserver, backend_roles=[], requestedTenant=null] Resolved [aliases=[], allIndices=[.opensearch_dashboards], types=[*], originalRequested=[.opensearch_dashboards], remoteIndices=[]] [Action [indices:admin/get]] [RolesChecked [own_index, kibana_server]]

Expected behavior
Dashboards should still be using .kibana* indices

OpenSearch Version
1.0.0-beta1

Dashboards Version
1.0.0-beta1

Plugins
security plugin v1.0.0.0-beta1

Additional Context
Please update any changes needed in security back end after this issue is resolved:
opensearch-project/security#1151

Host/Environment (please complete the following information):

• OS: ubuntu:latest docker image as of the day of ticket is opened

[ananzh]

We changed default index from .kibana --> .opensearch_dashboards for renaming and legal purpose. Changing default index cause permissions issue for security plugin because opensearch cluster with security plugin don’t have permissions for indices:admin/get. If add it back we still have .kibana index in our code which might cause legal issues. Even no legal issue, it is not a clean fork. Why we keep .kibana as our default index? My suggestion is that we should have opensearch cluster with security plugin to give permissions (add a role) .

[dblock]

Why we keep .kibana as our default index?

We won't, we just don't want to break absolutely everything for beta1.

[vrozov]

Changing .kibana to .opensearch_dashboards will likely cause not only backward compatibility issue, but will break multi-tenancy support on newly created cluster as well.

[dblock]

@saratvemulapalli is looking at how we can support old index names with backward compatibility, maybe an index alias can work.

[dblock]

We discussed undoing this change. Assigning the issue to @mihirsoni who had some strong feelings about it to resolve.

[mihirsoni]

@dblock as we have decided to restore it back, this will not be concern anymore, I am assigning this to @kavilla who is currently working on this.