### Does this PR have any customer impact?
No
### Type (Feature, Refactoring, Bugfix, DevOps, Testing, Perf, etc)
Refactor
### Does it involve schema level changes? (Table, Column, Index, UDF, etc level changes)
Yes
### Are you introducing any new config? If yes, do you have tests with and without them being set?
No
### Release Note (Refer [Template](../docs/release_notes/pgmongo_template.md))
### Description
Start porting schemas for SQL in documentdb_core.
Maintain back-compat by introducing CORE_SCHEMA_v2 to handle cases where the existing logic already depends on there being 2 core schemas
----
#### AI description (iteration 1)
#### PR Classification
Code refactoring to port schemas into `documentdb_core`.
#### PR Summary
This pull request refactors the code to port BSON type definitions and related functions into `documentdb_core`.
- `pg_helio_core/sql/types/bson--1.10-0.sql`: Replaced BSON type definitions with an include directive.
- Added `pg_documentdb_core/sql/types/bson--0.24-0.sql` and `pg_documentdb_core/sql/types/bson_typanalyze--0.24-0.sql` for BSON type and analysis functions.
- `pg_documentdb_core/sql/documentdb_core--0.24-0.sql`: Created `documentdb_core` schema and included BSON type definitions.
- Updated Makefiles (`Makefile.cflags`, `pg_helio_api/Makefile`, `pg_helio_core/Makefile`, `internal/pg_helio_distributed/Makefile`) to include new schema definitions.
- Updated `postgresql.conf` files to preload `pg_documentdb_core`.
### Does this PR have any customer impact?
No
### Type (Feature, Refactoring, Bugfix, DevOps, Testing, Perf, etc)
Refactor
### Does it involve schema level changes? (Table, Column, Index, UDF, etc level changes)
Yes
### Are you introducing any new config? If yes, do you have tests with and without them being set?
No
### Release Note (Refer [Template](../docs/release_notes/pgmongo_template.md))
### Description
move sql files from helio_core -> documentdb_core for schema files
----
#### AI description (iteration 1)
#### PR Classification
Code cleanup
#### PR Summary
This pull request moves SQL files from `helio_core` to `documentdb_core` to better organize schema files.
- Updated includes in `oss/pg_helio_core/sql/pg_helio_core--1.10-0.sql` to reference `pg_documentdb_core` paths.
- Modified `pgmongo/sql/pgmongo--1.14-6--1.15-0.sql` to include files from `pg_documentdb_core` instead of `pg_helio_core`.
- Adjusted `scripts/pipeline_check_sql_upgrades.sh` to validate and check SQL files in `pg_documentdb_core`.
- Updated `oss/pg_helio_core/Makefile` to include `OSS_SRC_DIR` for SQL file processing.
- Changed various `pgmongo/sql` files to reference `pg_documentdb_core` paths for BSON-related operations and schema definitions.
Vinod Sridharan