Disable and remove af_alg kernel module
It's a source of vulnerability, most recently the "Copy Fail" vulnerability (CVE-2026-31431). That one is already fixed, but according to Google crypto guy Eric Biggers [1], it's vulnerable by design. The only significant things it's used for (iwd and non-default cryptsetup algorithms) aren't supported in KDE Linux, so let's disable and remove this functionality.