Add forecast roles and permissions

[kaituo]

Description

Add forecast roles and indices; format roles.yml

• Added forecast_read_access and forecast_full_access roles in config/roles.yml to support the forecasting feature.
• Registered forecasting system indices within the AD plugin: TimeSeriesAnalyticsPlugin.java](https://github.com/opensearch-project/anomaly-detection/blob/main/src/main/java/org/opensearch/timeseries/TimeSeriesAnalyticsPlugin.java#L1722).
• Formatted config/roles.yml using check-permissions-order.js to satisfy code hygiene CI requirements; this formatting affected the ltr role but did not change any actual content

Is this a backport? If so, please add backport PR # and/or commits #, and remove backport-failed label from the original PR.
Not a backport.

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
Yes, opensearch-project/security-dashboards-plugin#2253

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

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.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 72.15%. Comparing base (b25deca) to head (2a4955f).
Report is 1 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #5386      +/-   ##
==========================================
- Coverage   72.19%   72.15%   -0.05%     
==========================================
  Files         382      382              
  Lines       23697    23697              
  Branches     3644     3644              
==========================================
- Hits        17109    17099      -10     
- Misses       4791     4802      +11     
+ Partials     1797     1796       -1     

see 8 files with indirect coverage changes

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[shikharj05]

Thanks @kaituo ! can you help check the failing CIs?