[MNG-8765] Maven Upgrade Tool (#2407)

## Maven Upgrade Tool (mvnup)
- New `mvnup` command-line tool with check/apply workflow
- Automatic POM discovery and multi-module project support
- Model version upgrades from 4.0.0 to 4.1.0 with namespace updates
- Intelligent inference to remove redundant information in Maven 4.1.0+ models
- Comprehensive plugin compatibility upgrades for Maven 4

### Plugin Compatibility & Upgrades
- Automatic plugin version upgrades for Maven 4 compatibility:
  * `maven-exec-plugin` → 3.2.0+
  * `maven-enforcer-plugin` → 3.0.0+
  * `flatten-maven-plugin` → 1.2.7+
  * `maven-shade-plugin` → 3.5.0+
  * `maven-remote-resources-plugin` → 3.0.0+
- Parent POM plugin detection with proper XML formatting
- Plugin management section creation with correct element ordering
- Property-based version management support

### Maven 4 Compatibility Fixes
- Fix unsupported `combine.children` attributes (`override` → `merge`)
- Fix unsupported `combine.self` attributes (`append` → `merge`)
- Remove duplicate dependencies in `dependencyManagement` sections
- Remove duplicate plugins in `pluginManagement` sections
- Comment out repositories with unsupported expressions
- Fix incorrect `parent.relativePath` pointing to non-existent POMs
- Create `.mvn` directory when not upgrading to 4.1.0 to avoid warnings

### Intelligent Model Inference
- Parent element trimming when parent is in same project
- Managed dependency removal for project artifacts
- Redundant subprojects list removal when matching direct children
- GroupId/version inference from parent when using relativePath
- Dependency inference that reverses Maven's resolution logic

### Advanced XML Processing
- Intelligent indentation detection supporting 2/4 spaces and tabs
- Document-wide formatting consistency preservation
- Proper element ordering following Maven POM schema standards
- pluginManagement placement before plugins sections
- Comprehensive JDOM-based XML manipulation with formatting preservation