distro/keys: minimize archlinux and tails signing keys

Re-export both keys through the new update_distro_signing_key scripts
to strip non-signing subkeys (encryption, authentication) and expired
subkeys that had accumulated in the in-tree copies.  Only the primary
key and currently-valid signing subkeys are retained.

  archlinux.key: 1168B -> 673B  (495B saved,   auth+encrypt subkeys removed)
  tails.key:     21282B -> 7376B (13906B saved, expired+non-signing subkeys removed)

Qubes OS keys (4.2, 4.3, weekly builds) were already minimal -- no change.

Fixes #2066.

This class of manual update has been needed repeatedly in the past and
was caught late each time, causing distro ISO verification failures in
the field for Tails and other supported distros:
  #1808 (issue: Tails key expired, ISOs unbootable)
  #1631 (PR: update tails.key, replay of manual steps)
  #1809 (PR: replay of #1631 for next Tails rotation)
  #2000 (PR: Tails 7.0 key, same manual process again)
  #1457 (PR: Arch Linux key update)
  #2033 (PR: Qubes OS 4.3 key addition)

TODO: wire bin/update_distro_signing_keys.sh into CI (e.g. a scheduled
      workflow) so upstream key rotations are detected automatically
      before they break users.

Signed-off-by: Thierry Laurion <insurgo@riseup.net>

Author: tlaurion

initrd/etc/distro/keys/archlinux.key

@@ -1,21 +1,14 @@
 -----BEGIN PGP PUBLIC KEY BLOCK-----
 
 mDMEY1+RVxYJKwYBBAHaRw8BAQdAd3XdZwOmmiALePwd26Bu3hPblAfHflGN+Lud
-gE2Qyby0JFBpZXJyZSBTY2htaXR6IDxwaWVycmVAYXJjaGxpbnV4LmRlPoiWBBMW
-CAA+AhsDBQkcMgSABQsJCAcCBhUKCQgLAgQWAgMBAh4BAheAFiEEPoDKGouJ9py6
-V9mKdqXvkFREmlwFAmNfk2gACgkQdqXvkFREmlzdiwD9Hf7TDfxBrJ1YwpD9lLtU
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-vu0MtCVQaWVycmUgU2NobWl0eiA8cGllcnJlQGFyY2hsaW51eC5vcmc+iJkEExYI
-AEECGwMFCRwyBIAFCwkIBwIGFQoJCAsCBBYCAwECHgECF4AWIQQ+gMoai4n2nLpX
-2Yp2pe+QVESaXAUCY1+TaAIZAQAKCRB2pe+QVESaXLQPAQCFeOXY4m9LPfMDNzrO
-IElLyh+w9p9PBa80AsAsjXGC1gEAy9Ymc3jnAj2MJDnby3b5WyNzDbjBMKVhv2Cv
-mDln0Aq4MwRjX5HTFgkrBgEEAdpHDwEBB0DjSWuxVrnVYEIcJlRJPmn54ReBGvqP
-+EYB2BVx5ZFPv4h+BBgWCAAmFiEEPoDKGouJ9py6V9mKdqXvkFREmlwFAmNfkdMC
-GyAFCRwyBIAACgkQdqXvkFREmlzEGwEAwvDuiUn1Mgw0x7/m0hXzveAAgLVdJWD+
-0/YiepxE9GoA/jCgNca2AuWyi416FYQkFtqtlIjWUb56hY5WlBvpNZIOuDgEY1+R
-VxIKKwYBBAGXVQEFAQEHQIhe0t8UMpN+G4c24ByW/Y1vu1m3C62KsvlRPzw/R0AN
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-BIAACgkQdqXvkFREmlynZgD+PlibATlapVxz6EprGMfnktevUlfWQwShRJ+w/x8I
-zyAA/0nOvoE7j4sdvg4QoW/s2nPYaDy8EK/XAMRT15eScYIH
-=FFYH
+gE2Qyby0JVBpZXJyZSBTY2htaXR6IDxwaWVycmVAYXJjaGxpbnV4Lm9yZz6ImQQT
+FggAQQIbAwUJHDIEgAULCQgHAgYVCgkICwIEFgIDAQIeAQIXgBYhBD6AyhqLifac
+ulfZinal75BURJpcBQJjX5NoAhkBAAoJEHal75BURJpctA8BAIV45djib0s98wM3
+Os4gSUvKH7D2n08FrzQCwCyNcYLWAQDL1iZzeOcCPYwkOdvLdvlbI3MNuMEwpWG/
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+ExYIAD4CGwMFCRwyBIAFCwkIBwIGFQoJCAsCBBYCAwECHgECF4AWIQQ+gMoai4n2
+nLpX2Yp2pe+QVESaXAUCY1+TaAAKCRB2pe+QVESaXN2LAP0d/tMN/EGsnVjCkP2U
+u1RUjgqnN7c/l145vlESwYTmhwEA+ftbKY8WhNR+uvF+aWypm1LP7YPkZ1cRZBg5
+OpS+7Qw=
+=6aX0
 -----END PGP PUBLIC KEY BLOCK-----