[FEATURE] Enable saltedpasswords by default

Implement auto-activation of saltedpasswords and rsaauth extension.


Resolves: #28273
Releases: 4.6

Change-Id: If96cbbffec59f436748e331783bc6fc94fb2b87d
Reviewed-on: http://review.typo3.org/3389
Reviewed-by: Jigal van Hemert
Tested-by: Jigal van Hemert
Reviewed-by: Kay Strobach
Tested-by: Kay Strobach
Reviewed-by: Helmut Hummel
Tested-by: Helmut Hummel