Bug fixes

Here's another alpha. If you'd like a beta, then please help with #2830988: [meta] 4.0.0 release roadmap.

Changes since 8.x-1.0-alpha4:

Alpha release snapshot.

• PAReview fixes
• Added hook_help()

• Fix image selection
• Implement username/password based authentication
• Implement token based API authentication

## [8.x-2.0]
### Added
- This changelog file
- New configuration fields for handle new logic for generate RSA keys
- Functionality for generate new RSA keys for test and production environment
- Possibility to define identifier field for the customer
- Payment service production public RSA key
- Possibility to display summary for configuration
- Possibility to display shop public key
- Update hook for create new table
- Logic for prevent against process 2 payment responses at same time.

## [8.x-2.0]
### Added
- This changelog file
- New configuration fields for handle new logic for generate RSA keys
- Functionality for generate new RSA keys for test and production environment
- Possibility to define identifier field for the customer
- Payment service production public RSA key
- Possibility to display summary for configuration
- Possibility to display shop public key
- Update hook for create new table
- Logic for prevent against process 2 payment responses at same time.