This commit extends the codebase to support both Anomaly Detection (AD) and forecasting. It contains a mixture of refactoring, renaming, removal of unused code, and package moving tasks. Here are the details:

Refactoring:
- `NodeStateManager.getAnomalyDetector` is now `getConfig`, with added functionality to fetch a Forecaster. The method comments are updated for clarity.
- Existing methods (`getFeatureSamplesForPeriods`, `getColdStartSamplesForPeriods`, `createPreviewSearchRequest`, `getMinDataTime`) have been added in `SearchFeatureDao` to handle forecasting logic.
- Adjusted `SecurityClientUtil` and `ParseUtils` to handle forecasting logic.
- Cleaned up `NodeState` to differentiate state for AD and forecasting.

Renaming:
- `AnomalyDetectorJob` is renamed to `Job` to facilitate reuse for forecasting.
- `NodeStateManager.getAnomalyDetectorJob` is renamed to `getJob`.
- Certain settings in `AnomalyDetectorSettings` are renamed to reflect they are meant for the AD setting. They have been marked as deprecated and new settings are used in `TimeSeriesSettings` instead.
- `IndexAnomalyDetectorJobActionHandler.getAnomalyDetectorJobForWrite` is renamed to `getJobForWrite`.
- `ADSafeSecurityInjector` is renamed to `TimeSeriesSafeSecurityInjector`.

Removing unused code:
- Synchronous code in `ClientUtil`, `IndexUtils`, and `CheckpointDao` is removed.
- The unused class `Throttler` is deleted.
- Mapping file names are changed, and the code referencing these files is adjusted.

Package moving:
- Several classes (`ClientUtil`, `MultiResponsesDelegateActionListener`, `SafeSecurityInjector`, `SecurityUtil`, `ExceptionUtil`, `SearchFeatureDao`, `CleanState`, `ExpiringState`, `MaintenanceState`, `NodeState`, `SingleStreamModelIdMapper`, `BackPressureRouting`) are moved to the respective `org.opensearch.timeseries` packages.

Miscellaneous:
- Fixed compiler failures caused by changes in opensearch-project/OpenSearch#8730 by replacing `DoubleArrayList` with `java.util.ArrayList`.
- Updates the Backwards Compatibility (bwc) version to align with the core's incremented bwc version as per [OpenSearch PR #8670](opensearch-project/OpenSearch#8670). This change prevents the issue described in [OpenSearch Issue #5076](opensearch-project/OpenSearch#5076).

Testing:
- Executed a `gradle build`.
- Added new tests for `ClientUtil` and `NodeStateManager`.

Signed-off-by: Kaituo Li <[email protected]>

Signed-off-by: Kaituo Li <[email protected]>

Signed-off-by: Kaituo Li <[email protected]>