### Does this PR have any customer impact?
No
### Type (Feature, Refactoring, Bugfix, DevOps, Testing, Perf, etc)
Refactoring
### Does it involve schema level changes? (Table, Column, Index, UDF, etc level changes)
No
### 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
Remove helio from file name
Remove helio references from source content except schema reference
Start local documentdb server with the documentdb extension
Regression tests using the documentdb extension
----
#### AI description (iteration 1)
#### PR Classification
Code cleanup
#### PR Summary
This pull request removes references to "helio" from the `documentdb_core` source code.
- `scripts/utils.sh`: Renamed variables from `preloadExtensions` to `preloadLibraries`.
- `pg_documentdb_core/include/utils/error_utils.h`: Updated function and macro names to replace "Helio" with "DocumentDB".
- `pg_documentdb_core/include/io/helio_bson_core.h` and `pg_documentdb_core/include/query/helio_bson_compare.h`: Moved to `pg_documentdb_core/include/io/bson_core.h` and `pg_documentdb_core/include/query/bson_compare.h`.
- `pg_documentdb_core/src/collation/collation.c` and `pg_documentdb_core/src/io/pgbson.c`: Replaced error codes and messages to use "DocumentDB" instead of "Helio".
- `scripts/validate_helio_extension_state.sh`: Added exceptions for certain files to skip validation for "helio" references.
### 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)
No
### 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 c files from pg_helio_core -> pg_documentdb_core
- Make helio_core, and other extensions depend on pg_documentdb_core as a lib dependency
----
#### AI description (iteration 1)
#### PR Classification
Code reorganization
#### PR Summary
This pull request moves source files from `pg_helio_core` to `pg_documentdb_core` to better organize the project structure.
- Deleted `oss/pg_helio_core/include/utils/helio_codes.txt`.
- Added `oss/pg_documentdb_core/src/pg_documentdb_core.c` for initializing the shared library.
- Updated `oss/Makefile.cflags` to include new paths and installation rules for `pg_documentdb_core`.
- Moved `oss/pg_helio_core/src/bson_init.c` and `oss/pg_helio_core/include/bson_init.h` to `oss/pg_documentdb_core/src/bson_init.c` and `oss/pg_documentdb_core/include/bson_init.h` respectively.
- Modified various `Makefile` files to set `USE_DOCUMENTDB_CORE` and adjust include paths.
Zinan Ren
Vinod Sridharan