Add JSON schema generation to build process for schemastore.org registration

- Modified bin/generate_component_manifest_files.py to generate JSON schema alongside pydantic models
- Added generate_json_schema() function with custom DateTimeEncoder to handle datetime objects
- Generated airbyte_cdk/sources/declarative/declarative_component_schema.json from YAML source
- JSON file can now be registered with schemastore.org for schema validation and auto-completion

Co-Authored-By: AJ Steers <[email protected]>

Author: devin-ai-integration[bot]