Draft: Migration from SearchGuard to EliatraSuite.

Migration from SearchGuard to EliatraSuite.

• Patching of main-os branch with 22 master commits using cherry picking following provided spreadsheet commits.xlsx
• Execution of Hendrik rename.sh script (Migration start:)
• Manual migration of leftovers, bugs fixing.
• Application of git/maven timeout workaround (Migration end:)
• Increase number of attempts to fetch sources running a job to 5
• Reverted _sg_ headers and jwt claims
• Repackaged all modules except plugin
• Migrated signals api and settings to alerting
• Renamed plugin eliatra-suite-opensearch-plugin
• Removed Spctl dependency #18 (closed)
• Api migrated to /_eliatra/security and config migrated to eliatra.security

Comments :

1. The sp_migration branch to be merged to main-os without squash to keep all history and not be deleted.
2. Deletion of this branch must be performed later when all three projects (plugin, spctl, integration-tests) will have been merged and fully tested.
3. This merge request need to be performed first, then spctl, then integration-tests in this order.
4. IT_BRANCH in .gitlab-ci-branch-specific.yml need to match integration-tests one when merged