feat: enhanced extension

[fengys1996]

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What's changed and what's your intention?

This pr mainly change

1. Added a constant value INFORMATION_SCHEMA_ALERTS_TABLE_ID.
2. Removed #[cfg(feature = "enterprise")] from InformationSchemaTableFactory related.
3. Added extension field for GreptimeOptions struct which stores some configuration related to extensions. The usage detail see test_read_config_file_with_extension.
4. Added Extension struct for flownode, frontend, standalone etc, which make extensions strongly typed.
5. Also remove the components field of the Flownode and Standalone instances, which breaks encapsulation.

PR Checklist

Please convert it to a draft if some of the following conditions are not met.

• I have written the necessary rustdoc comments.
• I have added the necessary unit tests and integration tests.
• This PR requires documentation updates.
• API changes are backward compatible.
• Schema or data changes are backward compatible.

[Copilot]

Pull Request Overview

This PR introduces an enhanced extension mechanism to support enterprise features in a more flexible way. The changes replace the previous plugin-based approach with a factory-based extension system that allows for better separation between open-source and enterprise code.

• Adds a new Extension type parameterization to GreptimeOptions for custom extension support
• Replaces plugin-based trigger DDL manager initialization with a factory-based approach
• Removes enterprise feature flag requirements from catalog information schema tables

Reviewed Changes

Copilot reviewed 23 out of 24 changed files in this pull request and generated 3 comments.

Show a summary per file

File	Description
src/cmd/src/options.rs	Adds generic extension parameter E to GreptimeOptions and introduces EmptyOptions for non-enterprise builds
src/cmd/src/extension/*.rs	New extension module with factory traits for standalone, frontend, and metasrv components
src/meta-srv/src/metasrv/builder.rs	Updates builder to accept and use extension for trigger DDL manager creation
src/meta-srv/src/bootstrap/*.rs	Adds extension module and updates metasrv_builder signature to accept extension
src/common/meta/src/ddl_manager.rs	Renames method from with_trigger_ddl_manager to with_trigger_ddl_manager_opt
src/cmd/src/standalone.rs	Updates to use extension-based factory for trigger DDL manager and information schema tables
src/cmd/src/frontend.rs	Updates to use extension-based factory for information schema tables
src/cmd/src/metasrv.rs	Adds extension parameter to build methods
src/cmd/src/flownode.rs	Removes enterprise Components struct (no longer needed)
src/cmd/src/datanode.rs	Adds extension generic parameter to types and methods
src/catalog/src/*.rs	Removes enterprise feature flags from information schema table factory support
src/cmd/tests/load_config_test.rs	Updates test code to use EmptyOptions generic parameter
src/cmd/Cargo.toml	Removes catalog/enterprise from enterprise feature dependencies

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[Copilot]

Pull Request Overview

Copilot reviewed 25 out of 26 changed files in this pull request and generated 2 comments.

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[Copilot]

Pull Request Overview

Copilot reviewed 26 out of 28 changed files in this pull request and generated 7 comments.

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[MichaelScofield]

Seems "extension" is functionally overlapping with existed "plugins". Unless there are some hard problems that current plugins can't resolve while extension can, I'm inclined to optimize plugins instead. WDYT @sunng87 @fengjiachun

[sunng87]

Yes, is there any chance we can reuse plugin mechanism, or just use wrapper in downstream repos for this?