feat(backup): add ability to export uninstalled packages with their description

[edgy-b]

• fixed some deepsource issues

Resolves #173

[deepsource-io]

Here's the code health analysis summary for commits 2de6e73..4e954c0. View details on DeepSource ↗.

Analysis Summary

Analyzer	Status	Summary	Link
Rust	❌ Failure	❗ 11 occurences introduced 🎯 12 occurences resolved	View Check ↗
Test coverage	✅ Success	❗ 22 occurences introduced 🎯 15 occurences resolved	View Check ↗

Code Coverage Report

Metric	Aggregate	Rust
Branch Coverage	100%	0%
Composite Coverage	1.8% (down 0.2% from main)	1.8% (down 0.2% from main)
Line Coverage	1.8% (down 0.2% from main)	1.8% (down 0.2% from main)
New Branch Coverage	100%	100%
New Composite Coverage	0.8%	0.8%
New Line Coverage	0.8%	0.8%

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[adhirajsinghchauhan]

Code passes the eye test, but are we sure we want to stick with txt? This looks weird to me:

Name: <app 1>
Description: <multiline
text>
-------------------------------------------------------------------
Name: <app 2>
Description: <text>

I'd rather have it exported in other formats such as CSV. Can still be opened in a text editor, but at least users could potentially use other programs to view/filter through everything.

[adhirajsinghchauhan]

If we end up sticking with txt, consider making this separator string a const somewhere up above, so that we can reuse it elsewhere.