Don't rely on transparent decompression in list_aur

[espeer]

The current AUR package list code relies on the reqwest client library to transparently decompress the packages.gz file. This only works if the server provides the 'Content-Encoding: gzip" HTTP header, which appears to have changed recently.

This patch explicitly decompresses the package list if no encoding information is provided by the server.

Fixes: https://github.com/Morganamilo/paru/issues/1447

[q234rty]

There are two other uses of packages.gz in completion.rs and search.rs which both need to be fixed.

[espeer]

Pushed v3 to address completion.rs and search.rs.

[navoyan]

In case someone manually syncs this patch and wonders why it doesn't fix anything, try deleting ~/.cache/paru/packages.aur. Thank you for the fix, BTW