fix: update references to manifest to user proper terminology

[amoeba]

Updates code where we refer to "driver list" as a manifest.

Follow-on to #21

[amoeba]

Rebased, will merge when CI is green.

[amoeba]

Hm, this looks like it uncovered a test flake. The test doesn't fail locally.

The difference is

• expected:
  • installing\r\n[✓] verifying signature
• actual:
  • installing\r\n[/] verifying signature...\r\n\r\x1b[4A\n\n\n[✓] verifying signature\r\n\nI

so it looks like it's capturing the progress spinner. I'm going to merge this but thought I'd make a note.