feat: improve Zabbix multi-version compatibility and introduce local development environment

This update enhances compatibility across multiple Zabbix versions and introduces tools for easier local development and testing.

Key improvements and verified version support:
- Verified Zabbix version support: 6.2, 6.4, 7.0, and 7.4.
- Version-specific feature handling:
  - `history.push` is enabled only for Zabbix 7.0+; older versions skip it with a clear error or notice.
  - Conditional JSON-RPC authentication: the `auth` field is automatically added to the request body for versions older than 6.4.
  - Implemented static Zabbix version caching in the datasource to minimize redundant API calls.
- Query optimization refinements:
  - Added mapping for implied fields (e.g., `state` -> `items`, `deviceType` -> `tags`).
  - Automatically prune unnecessary Zabbix parameters (like `selectItems` or `selectTags`) when not requested.
- Local development environment:
  - Added a new `zabbix-local` Docker Compose profile that includes PostgreSQL, Zabbix Server, and Zabbix Web.
  - Supports testing different versions by passing the `ZABBIX_VERSION` environment variable (e.g., 6.2, 6.4, 7.0, 7.4).
  - Provided a sample environment file at `samples/zabbix-local.env`.
- Documentation and Roadmap:
  - Updated README with a comprehensive version compatibility matrix and local environment instructions.
  - Created a new guide: `docs/howtos/local_development.md`.
  - Updated maintenance guides and added "Local Development Environment" as an achieved milestone in the roadmap.
- Test suite enhancements:
  - Improved Smoketest and RegressionTest executors with more reliable resource cleanup and error reporting.
  - Made tests version-aware to prevent failures on older Zabbix instances.

BREAKING CHANGE: Dropped Zabbix 6.0 specific workarounds; the minimum supported version is now 6.2.

.gitignore

@@ -74,10 +74,7 @@ web_modules/
 
 # dotenv environment variable files
 .env
-.env.development.local
-.env.test.local
-.env.production.local
-.env.local
+.env.*
 
 # parcel-bundler cache (https://parceljs.org/)
 .cache