Initialize api tokens index if it doesn't exist

[derek-ho]

Description

Initializes a new index for API tokens if it doesn't exist

Issues Resolved

Closes: #4900

Is this a backport? If so, please add backport PR # and/or commits #, and remove backport-failed label from the original PR.

Do these changes introduce new permission(s) to be displayed in the static dropdown on the front-end? If so, please open a draft PR in the security dashboards plugin and link the draft PR here

Testing

[Please provide details of testing done: unit testing, integration testing and manual testing]

Check List

• New functionality includes testing
• New functionality has been documented
• New Roles/Permissions have a corresponding security dashboards plugin PR
• API changes companion pull request created
• Commits are signed per the DCO using --signoff

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[codecov]

Codecov Report

Attention: Patch coverage is 88.88889% with 1 line in your changes missing coverage. Please review.

Project coverage is 71.43%. Comparing base (3c635c9) to head (b8adfb1).

Files with missing lines	Patch %	Lines
...ecurity/configuration/ConfigurationRepository.java	88.88%	1 Missing ⚠️

Additional details and impacted files

@@                 Coverage Diff                 @@
##           feature/api-tokens    #4899   +/-   ##
===================================================
  Coverage               71.43%   71.43%           
===================================================
  Files                     334      334           
  Lines                   22509    22511    +2     
  Branches                 3582     3582           
===================================================
+ Hits                    16079    16081    +2     
- Misses                   4638     4639    +1     
+ Partials                 1792     1791    -1     

Files with missing lines	Coverage Δ
...g/opensearch/security/support/ConfigConstants.java	95.23% <ø> (ø)
...ecurity/configuration/ConfigurationRepository.java	76.69% <88.88%> (-0.21%)	⬇️

... and 3 files with indirect coverage changes

[DarshitChanpura]

why do we need this block?

[derek-ho]

This is necessary as without it we could try to create an index before the cluster is ready to handle this request. @DarshitChanpura @cwperks Do you folks think we still need this check though? As that check should already be performed by the creation of the opendistro_security index, depending on the value of "plugins.security.allow_default_init_securityindex" setting. In any case I was just taking inspiration from the creation of the opendistro_security index.

[DarshitChanpura]

why do we need to explicitly stashContext here?

[derek-ho]

Like the above, this is taken from the creation of opendistro_security index, which I assume has this to handle edge cases since the security index may not be initialized yet. Again not completely sure if its needed but I think it is fine?

[cwperks]

I think this class should be reserved for initializing the security index. The security index will always need to be created on bootstrap.

For most plugins, I believe they create a system index when its needed if it doesn't exist instead of creating it on bootstrap. i.e. A user tries to issue an auth token and security tries to store the metadata, but the index doesn't exist so create it at that time.

See this class from AD plugin: https://github.com/opensearch-project/anomaly-detection/blob/main/src/main/java/org/opensearch/ad/indices/ADIndexManagement.java