Add Show Imports decompiler setting

[YanisBft]

Nothing major, just a new "Show Imports" setting when decompiling classes.

Closes #136

[Gegy]

Does this work for imports of obfuscated classes? I'm not sure how it would get around the issue with displaying imports mentioned in #136.

[YanisBft]

This PR only adds the option, but yes the imports are a bit limited, as Procyon only shows library imports, and CFR shows all but with obfuscated names

[Gegy]

The option might be a bit misleading and potentially have very limited scope for use.

[liach]

These imports will be confusing as well, as they include more imports than what's assumed by javadoc