This commit introduces a new ServiceIdentifier system that allows applications
to be uniquely identified and tracked. The implementation includes:

- ServiceIdentifier actor that stores app type, label, and version
- Application extension to store and retrieve identifiers
- Storage mechanism using the Vapor application storage system
- Custom string representation for easy debugging
- Comprehensive test suite validating functionality

The system prevents duplicate registrations of the same app type and provides
async accessor methods to maintain thread safety.

- Replace getID/setID methods with async description property and register method
- Add new ServiceIdentity struct to improve identifier handling
- Make ServiceIdentity Codable, ExpressibleByStringLiteral and CustomStringConvertible
- Implement parsing of ID components (id, label, version) from string representation

- Adjust indentation from 2 spaces to 4 spaces throughout the file
- Fix whitespace and line breaks for better readability
- Reorder extensions to improve logical flow
- Move ObjectIdentifier extension to the top of the file
- Add empty line after ServiceIdentifier init for consistent spacing
- Maintain consistent brace style across all declarations

- Rename `ServiceID` -> `ServiceIdentity` for application property
- Rename `ServiceIdentifier` -> `ServiceIdentifiable` for actor class
- Rename `ServiceIdentity` -> `ServiceIdentifier` for the Codable struct
- Adapt method names for consistency: `getId()` -> `description`, `setId()` -> `register()`
- Update test cases to use new naming conventions
- Improve variable naming with consistent ID capitalization
- Fix string property name `serviceidentifierString` -> `serviceidentityString`