This reverts commit c8a13555.

Sadly, Borg says this is not a good idea: https://borgbackup.readthedocs.io/en/stable/faq.html#can-i-backup-from-multiple-servers-into-a-single-repository

Spoiler:  This won't work, Borg does not guarantee consistency with
parallel writers to the same repo as I now found out.

It's not really a key, and not really public, but not secret either.
This way, the tests can run.

weekly nixpkgs update (2022-04-25)

See merge request !294

Log retention policy module

See merge request !290

Add flo to prod: ssh key + root access

See merge request !292

Add flo's ssh key to the staging grid root user authorized_keys

See merge request !291

Configure journald to discard logs before they're older than 30 days

Closes privatestorageops#221

See merge request !285

This is only semi correct. We keep logs up to what's specified in the privacy
policy.  Currently, that is implemented as keeping them for up to 30 days on
the individual nodes as well as on the central Loki server.

Fix docs code blocks

See merge request !289

nixpkgs update 2022-04-13

See merge request !287

Add update-nixpkgs / diff-closures documentation

See merge request !288

bump PaymentServer to version exposing more info

Closes privatestorageweb#226

See merge request !284

weekly nixpkgs update (2022-03-28)

See merge request !282

weekly nixpkgs update (2022-03-21)

See merge request !280

```
VirtualBox-GuestAdditions: 6.1.30-5.10.103 → 6.1.30-5.10.106
cpupower: 5.10.103 → 5.10.106
ena: 2.5.0-5.10.103 → 2.5.0-5.10.106
expat: 2.4.4 → 2.4.7
getent-glibc: 2.33-117 → 2.33-123
glibc: 2.33-117 → 2.33-123
glibc-locales: 2.33-117 → 2.33-123
initrd-linux: 5.10.103 → 5.10.106, +75.7 KiB
linux: 5.10.103, 5.10.103-modules → 5.10.106, 5.10.106-modules
locale-glibc: 2.33-117 → 2.33-123
nixos-system-monitoring: 21.11.336340.2ebb6c1e5ae → 21.11.336589.2c66a7a6e03
nixos-system-payments: 21.11.336340.2ebb6c1e5ae → 21.11.336589.2c66a7a6e03
nixos-system-storage001: 21.11.336340.2ebb6c1e5ae → 21.11.336589.2c66a7a6e03
nixos-system-storage002: 21.11.336340.2ebb6c1e5ae → 21.11.336589.2c66a7a6e03
nixos-system-storage003: 21.11.336340.2ebb6c1e5ae → 21.11.336589.2c66a7a6e03
nixos-system-storage004: 21.11.336340.2ebb6c1e5ae → 21.11.336589.2c66a7a6e03
nixos-system-storage005: 21.11.336340.2ebb6c1e5ae → 21.11.336589.2c66a7a6e03
nixos-system-storage1: 21.11.336340.2ebb6c1e5ae → 21.11.336589.2c66a7a6e03
nixos-system-storage2: 21.11.336340.2ebb6c1e5ae → 21.11.336589.2c66a7a6e03
openssl: 1.1.1m → 1.1.1n
stage: -19.4 KiB
udhcp: ∅ → ε
util-linux: 2.37.3 → 2.37.4
zfs-kernel: 2.1.2-5.10.103 → 2.1.3-5.10.106
zfs-user: 2.1.2 → 2.1.3, +14.0 KiB

```