bytecode viewer doesn't export non class files

JRE: 1.8.0_321
version: Bytecode-Viewer-2.11.0

steps to reproduce:
- take this jar [abyssalcraft-1.3.0-src.jar.zip](https://github.com/Konloch/bytecode-viewer/files/8105175/abyssalcraft-1.3.0-src.jar.zip)
- click decompile and save all classes with either fernflower or procyon
- notice it only does class files and doesn't preserve the jar

Why: this is a hassle if you have a whole bunch of resources scattered throughout the jar or even non java files like html, py etc... if you intended on having it save only classes for save all classes then you should provide decompile and save all. I don't recall it skipping non class files before but I could be wrong.

Reproduce the issue in Bytecode Viewer 2.11.0 using the attached abyssalcraft archive, selecting decompile and save all classes with FernFlower or Procyon. Trace the save-all export path and verify that the resulting archive preserves non-class resources such as HTML and Python files while still exporting decompiled classes.

Written by the indexing model from the issue text.