Switch musicdolphin from a Pi 4 to a Pi 5

The SD card moves over as is, so:
- pi_standard_setup can install the Pi 5 kernel (linux-image-rpi-2712, an arm64
  package on the armhf userland), which a Pi 4 image lacks. Opt-in via
  pi_standard_setup_install_pi5_kernel.
- The Pi is powered through the HiFiBerry board's GPIO header, so it cannot negotiate
  a 5A supply and would cap USB at 600mA. pi_hifiberry_amp sets
  usb_max_current_enable=1 when hifiberry_powers_pi is true (default false).
- The DHT22 poller is off: Adafruit_DHT bit-bangs BCM283x registers, which the Pi 5
  no longer has (GPIO sits behind the RP1 chip).

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

roles/pi_standard_setup/defaults/main.yml

@@ -9,3 +9,8 @@ pi_standard_setup_wifi_pass_url: "bauer_wifi" # has to be in keepass with url "w
 ansible_ssh_pass: "raspberry"
 ansible_become_password: "raspberry"
 ansible_become: true
+
+# Install the Pi 5 (BCM2712) kernel, kernel_2712.img (an arm64 package, hence the :arm64 on
+# the armhf userland). A card imaged on a Pi 4 does not have
+# it, and a Pi 5 will not boot without. Harmless on a Pi 4, which keeps its own kernel.
+pi_standard_setup_install_pi5_kernel: false