main/devicepkg-utils: install default /etc/deviceinfo (MR 4283)

Previously, every device package would package its own /etc/deviceinfo
file, generating a conflict with every other device package. In a
previous commit we have moved the path to /usr/share/deviceinfo, but
we still want to install a sample "/etc/deviceinfo" file to guide
users on how to use the new features. This has the additional benefit
that there is only one of those files in the whole distro. However,
there is no dependency ordering between the device packages and
devicepkg-utils, so there's no warranty of which will be installed
first. Therefore, to avoid a conflict on most likely every user
upgrade, we use postmarketos-mvcfg.

main/devicepkg-utils/APKBUILD

@@ -1,16 +1,25 @@
 pkgname=devicepkg-utils
 pkgver=0.2.0
-pkgrel=0
+pkgrel=1
 pkgdesc="Utilities for interacting with device packages"
 url="https://postmarketos.org"
 arch="noarch"
 license="MIT"
-source="source_deviceinfo"
+depends="postmarketos-mvcfg"
+install="$pkgname.pre-upgrade"
+source="
+	etc-deviceinfo
+	source_deviceinfo
+"
 options="!check"
 
 package() {
 	install -Dm644 "$srcdir"/source_deviceinfo -t "$pkgdir"/usr/share/misc
+
+	install -Dm644 "$srcdir"/etc-deviceinfo "$pkgdir"/etc/deviceinfo
+	postmarketos-mvcfg-package "$pkgdir" "$pkgname"
 }
 sha512sums="
+ef2181d7072b4ef62c11d3f50677fcd455e50cf89a3110e67fcaa6058ea695f101ded48b1442758494e3d23a97cdd93df6669656f329037020ba715af4341b55  etc-deviceinfo
 a6e4f57280bed21fe3ac480eaa582c14fa8337d77386ff92c3e271818b5a028cac2a4f557ecfe9f7432e23a6dadd33bdc6b429a0e5e29cce2602b2a6e58a8bdd  source_deviceinfo
 "

main/devicepkg-utils/devicepkg-utils.pre-upgrade

@@ -0,0 +1,5 @@
+#!/bin/sh
+
+postmarketos-mvcfg-pre-upgrade \
+	devicepkg-utils \
+	/etc/deviceinfo

main/devicepkg-utils/etc-deviceinfo

@@ -0,0 +1,8 @@
+# Override settings from /usr/share/deviceinfo/deviceinfo with this file.
+# After modifying: Some settings require running "mkinitfs" as root and/or
+# a reboot to apply.
+# Reference: https://postmarketos.org/deviceinfo
+
+# Examples:
+# deviceinfo_kernel_cmdline_append=" PMOS_NOSPLASH"
+# deviceinfo_usb_network_function="ncm.usb0"