feat: greptimedb plugin as skywalking backend storage

[killme2008]

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[Copilot]

Pull request overview

This PR adds GreptimeDB as a new storage backend for Apache SkyWalking. GreptimeDB is an open-source, cloud-native time-series database. The implementation uses a dual-protocol architecture: gRPC for high-throughput asynchronous writes (port 4001) and MySQL protocol via JDBC for queries and DDL (port 4002). The plugin implements all 36 DAO interfaces required by SkyWalking and leverages GreptimeDB's native features including TTL management, merge modes for metrics, and append mode for records.

Changes:

• Added complete GreptimeDB storage plugin with client, schema management, and 36 DAO implementations
• Integrated plugin into build system and module configuration
• Added comprehensive unit tests, integration tests, and E2E tests
• Added documentation for setup and configuration

Reviewed changes

Copilot reviewed 63 out of 63 changed files in this pull request and generated 3 comments.

Show a summary per file

File	Description
pom.xml	Added GreptimeDB plugin module and Maven dependencies including ingester SDK, gRPC, and MySQL connector
GreptimeDBStorageProvider.java	Main module provider registering all storage services and DAO implementations
GreptimeDBStorageClient.java	Dual-protocol client managing gRPC connection for writes and JDBC connection pool for reads
GreptimeDBStorageConfig.java	Configuration class for connection settings, TTLs, and performance tuning
GreptimeDBConverter.java	Data type mapping and conversion utilities between SkyWalking and GreptimeDB
GreptimeDBTableInstaller.java	Schema installation with DDL generation for tables, indexes, and TTL options
SchemaRegistry.java	Caches table schemas and column mappings for write operations
dao/*.java	36 DAO implementations covering metrics, traces, logs, profiling, and management data
test/**/*.java	Unit tests, integration tests with Testcontainers
e2e-v2/cases/storage/greptimedb/*	E2E test configuration and scenarios
docs/**/*.md	Setup documentation and architecture description
application.yml	Configuration template with environment variables

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[Copilot]

Pull request overview

Copilot reviewed 67 out of 67 changed files in this pull request and generated 3 comments.

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