Add Ctrl + U shortcut

[Botan626]

Checklist

• [X] I read and understood ASF-ui's Contributing Guidelines
• [X] I also read FAQ
• [X] My idea doesn't duplicate existing ASF-ui functionality described on the wiki
• [X] I believe that my idea falls into ASF-ui's scope and should be offered as part of ASF-ui built-in functionality
• [X] This is not ASF suggestion

Enhancement purpose

Ctrl + U Delete from the cursor to the start of the line. https://itsfoss.com/linux-terminal-shortcuts/

instead of using CTRL + A and then CTRL + K, the user could only use Ctrl + U

don't forget to add description for it here: https://github.com/JustArchiNET/ASF-ui/wiki/Features#shortcuts