[4.0] RTL: Login-Form "Forget Username / Password" need align right

Steps to reproduce the issue

As Title say:

System information

• Nightly Build 4.0.0-alpha5-dev
• Multilingual Sample Data (French, German DE, Persian)
• Template: Cassiopeia
• macOS Sierra, 10.13.6
• Firefox 61 (64-bit)

CloudAccess.net

• PHP 7.1.15
• MySQLi 5.7.18-cll-lve

[infograf768]

Closing as we have a patch
#21402