Move input validation to separate thread

title.

Currently validation can block the GUI thread which is an absolute no-go. we should implement a validation-thread which checks every field we give it periodically.

Benefit: Said thread can edit the text in the fields if appropriate. Example:

• Java Args : https://git.griefed.de/Griefed/tests/-/blob/editJavaArgsInString/src/main/java/de/griefed/Main.java
• Suggested directories for copy dirs
• and so on