ATLAS-5313: Ability to Export Apache Atlas Business Glossary to Excel/CSV from server-side

[UmeshPatil-1]

What changes were proposed in this pull request?

ATLAS-5313 Ability to Export Apache Atlas Business Glossary to Excel/CSV from server-side

This PR adds server-side APIs to search and export Business Glossary content (terms, categories, and related metadata to CSV and XLSX, scoped to one or more glossaries. It follows the same async download pattern used by Basic Search (create_file --> download/status → download/{filename}).

Integration layer (intg)

• Added AtlasConfiguration.GLOSSARY_EXPORT_MAX_ROWS (default: 5000) to cap export row count.
• Added GlossaryExportParameters, GlossarySearchParameters, GlossarySearchResult, and GlossaryExportRow model classes for export/search request and response handling.

Repository layer (repository)

• Extended GlossaryService with glossary search and async export support.
• Added export pipeline components:
• GlossarySearchBuilder — builds glossary-scoped search results
• GlossaryExportDataCollector — collects glossary terms/categories for export
• GlossaryExportFilter — applies export filters
• GlossaryExportParameterMapper — maps REST parameters to export configuration
• GlossaryExportUtils — shared export utilities
• GlossaryExportWriter — writes CSV/XLSX output
• GlossaryExportDownloadTask / GlossaryExportDownloadTaskFactory — async file generation
• Added unit tests: GlossaryExportFilterTest, GlossaryExportUtilsTest, GlossaryExportWriterTest, GlossarySearchBuilderTest, and updated GlossaryServiceTest.

Web application layer (webapp)

• Added REST endpoints under v2/glossary:
  POST /v2/glossary/search — glossary-scoped search
  POST /v2/glossary/download/create_file — queue CSV/XLSX export
  POST /v2/glossary/create_file — alias for UI compatibility
  GET /v2/glossary/download/status — export job status for current user
  GET /v2/glossary/download/{filename} — download completed export file
• Extended GlossaryRESTTest with unit tests for the new endpoints.

Export fields supported
Export rows include glossary term/category metadata such as name, glossary name, short/long description, status, classifications, and custom attributes, as defined in the JIRA requirements.

How was this patch tested?

Unit tests
All glossary-related unit tests were executed and passed:
Repository module:Result: 68 tests passed, 0 failures
Webapp module: Result: 67 tests passed, 0 failures

Module compile verification

• intg, repository, and webapp modules compile successfully with the new APIs and models.
• Remaining project modules (bridges, distro, etc.) were built separately; glossary changes compile cleanly within the core modules.

Manual / integration testing
Manual REST testing of the new glossary export/search APIs was performed during development (documented locally).