Fix repository checker issues: remove non-existent versions, add missing plugins, update dependencies, add testing framework

[Copilot]

This PR addresses all critical errors and major warnings identified by the ioBroker repository checker to ensure compliance with repository standards and enable future stable repository updates.

Key Changes

Critical Error Fixes (E-series)

• E254: Removed non-existent versions (0.4.15-alpha.1, 0.4.0, 0.2.27) from common.news in io-package.json that don't exist on NPM
• E524: Added missing @alcalzone/release-script-plugin-iobroker plugin dependency for release script functionality
• E525: Added missing @alcalzone/release-script-plugin-license plugin dependency for release script functionality

Major Warning Fixes (W-series)

• W028: Updated minimum Node.js version requirement from >=18 to >=20 in package.json engines
• W132: Reduced common.news entries from 15 to 7 (latest versions only) to meet repository limits
• W135: Added required common.tier property (set to tier 2) in io-package.json
• W156: Updated dependency versions to recommended levels:
  • admin from >=6.17.14 to >=7.6.17
  • js-controller from >=5.0.19 to >=6.0.11
• W252: Aligned version between package.json and NPM (updated from 0.4.15-alpha.1 to 0.4.15)

Additional Improvements

• Added @iobroker/testing v5.1.1: Added as dev dependency to provide enhanced testing capabilities and framework consistency

Version Cleanup

The news section now contains only the latest 7 versions that exist on NPM:

• 0.4.14, 0.4.12, 0.4.11, 0.4.10, 0.4.9, 0.4.8, 0.4.7

Removed 8 older entries to comply with repository builder limits while preserving Ukrainian translations for all remaining entries.

Dependencies

• Verified axios is needed (actively used in lib/tools.js)
• Added proper versions of release script plugins that are available on NPM
• Added @iobroker/testing for enhanced testing capabilities and framework consistency
• Synchronized package-lock.json to ensure dependency consistency
• All JSON files validated and linting passes

This resolves all blocking issues for stable repository updates while maintaining backward compatibility and existing functionality.

Fixes #1102.

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[DutchmanNL]

@copilot ensure "@iobroker/testing" dependency is added as dev dependency and latest version and ensure package and package-lock are in sync

[Copilot]

@copilot ensure "@iobroker/testing" dependency is added as dev dependency and latest version and ensure package and package-lock are in sync

Added @iobroker/testing v5.1.1 as dev dependency and synchronized package-lock.json. The package is now properly installed and all dependencies are in sync. Linting and tests continue to pass. (commit: 3d8b2c8)