Update API version, add payment models & tests
- Bump version to 3.1.0
- Add new online payment models and types
- Introduce `Payment` class for handling transactions
- Replace `ts-node` with `vitest` for testing
- Remove unused hashing functions (sha1, md5)
- Refactor query parameter handling in services
- Add paginated response type for direct billing service
- Implement unit tests using `vitest`
- Delete old test scripts

v3.0.3
Bump version to 3.0.3

v3.0.2
Expanded payment-related keywords in package.json

v3.0.1
Updated package version

v3.0.0
Refactored SMS XML handling code

v2.3.0
Update eslintignore, package.json, and models for DirectBilling and S...

This commit adds a new property 'complete' to the interface DbServiceNotify in db.service.ts file. It also updates the DirectBilling class in directbilling.ts file to use this new property instead of 'success'.

v2.2.3
Add steamid to DirectBilling payment request parameters

v2.2.2
Additional headers with informations

v2.2.1
Fix used_at casting to date in sms code verification