AbaClient: äldre versioner att ladda ner

Fixed bugs:

- Links with mailto:, tel: and callto: are now opening correctly again
- Opening AbaClients with start parameters is working correctly again
- Various other bug fixes and stability improvements

Release Notes:

- Removal of the ability to import AbaStart links
- Removal of the AbaClient setting 'Clear browser cache at start'. This option is no longer required due to improvements in the background.
- Update of Java versions to 17 and 21
- Automatic deletion of the .abalink file from the Downloads directory

Release Notes:

- Login is only possible via the standard web browser
- Java 8 has been removed
- Conversion from 32-bit to 64-bit
- JxBrowser has been removed

AbaClient 3 supports Abacus versions from version 2019 onwards.
Older Abacus installations can no longer be started with this client.

Release Notes:

- Bugfix: Printing under macOS, in combination with Abacus Version 2024 not possible.
- The Chromium browser integrated in the AbaClient has been updated to version v7.38.0.
- New code signing certificate for Abacus installation from 15.07.2024
- Various bug fixes