refactor(wpcarro/gnupg): Improve UX for gnupg/{import,export}.sh

TL;DR:
- Ensure that export.sh -> import.sh -> export.sh can round-trip without
  intermediate tools.
- Remove default values for variables like ${1}, which only seem to complicate
  things.
- Add `trap cleanup EXIT` to scripts.
- Remove noisy full-paths from `zip` (note: a more intuitive, less configurable
  `zip`, `unzip` should exist).

Change-Id: Ibbd98d1f0156639138175fcb89e9dfbd17fdae5f
Reviewed-on: https://cl.tvl.fyi/c/depot/+/4993
Tested-by: BuildkiteCI
Reviewed-by: wpcarro <wpcarro@gmail.com>

users/wpcarro/configs/.gnupg/import.sh

@@ -1,13 +1,28 @@
 #!/usr/bin/env bash
 
-set -e
+set -euo pipefail
 
 # Run this script to import all of the information exported by `export.sh`.
-# Usage: ./import.sh path/to/directory
+# Usage: ./import.sh path/to/export.zip
 
-gpg --import "$1/public.asc"
-gpg --import "$1/secret.asc"
-gpg --import-ownertrust "$1/ownertrust.txt"
+if [ -z "${1+x}" ]; then
+  echo "You must specify the path to export.zip. Exiting..."
+  exit 1
+fi
+
+destination="$(mktemp -d)"
+
+function cleanup() {
+  rm -rf "${destination}"
+}
+trap cleanup EXIT
+
+unzip "${1}" -d "${destination}" >/dev/null
+
+gpg --import "${destination}/public.asc"
+gpg --import "${destination}/secret.asc"
+gpg --import-ownertrust "${destination}/ownertrust.txt"
 
 # Run this at the end to output some verification
 gpg --list-keys
+gpg --list-secret-keys