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

```

Fix RAID alert going off with zero degraded arrays

See merge request !279

This should fix the current alerts for our RAID arrays.
It's only "should" because I can't test it proper without said
RAID arrays in the dev or staging machines.

bump PaymentServer

See merge request !276

bump nixpkgs, esp. for linux 5.10.103

See merge request !277

Factoring improvements (VPN client, monitoring exporters)

See merge request !271

Grafana: Payment dashboard: Revert "Redemption" back to old-style Graph panel

See merge request !270

nixpkgs update 2022-02-28

See merge request !275

Since that describes it better, especially now that I have
moved the one line that wasn't about the VPN out of it.

Tom Prince authored 3 years ago and Florian Sesser committed 3 years ago

This includes the host-based metrics collector, and the VPN client setup (including key deployment).

The newer "Time Series" panel does not support two axes.

Grid configs: clean up config imports

See merge request !269

Grafana: Revamp network errors panel, add (experimental) PSI panels

See merge request !268

Miscellaneous changes

See merge request !262

... and fix that option the other commit introduced

Nix sometimes seems peculiar about merging sets?

define groups for tahoe nodes

See merge request !265