[halium-16.0] snippets: ubports: track bootable/recovery and external/{gpg,lvm2}

[JamiKettunen]

Compiles with https://github.com/JamiKettunen/android_external_gpg/tree/halium-16.0 which perhaps should be imported/merged too depending on how the changes want to be done; took the liberty to also get proper diff to upstream tarball and bumped it from v1.4.13 (late 2012) -> v1.4.23 (mid 2018) so it's at least on the latest legacy branch version

OTAs don't currently work due to busybox not being installed:

/system/bin/system-image-upgrader[576]: busybox: inaccessible or not found

Kernel versions <4.14 will also need a revert of LineageOS/android_bionic@10893f6 or preferably some cleaner solution:

[    2.337717]  (5)[1:init]arc4random data MADV_WIPEONFORK failed: Invalid argument
[    2.337826]  (5)[1:init]libc: arc4random data MADV_WIPEONFORK failed: Invalid argument
[    2.338081] -(5)[1:init]Kernel panic - not syncing: Attempted to kill init! exitcode=0x00007f00

Kernel v4.4.153 OnePlus 5 boots while v4.4.146 Volla Phone doesn't (and doesn't seem like a kernel panic either); similar was fixed previously with Halium/hybris-patches@eab63d2 but should be redundant with https://github.com/Halium/hybris-patches/blob/halium-16.0/system/core/0023-halium-make-cgroup-setup-failures-non-fatal-in-conta.patch

We could also check if the generated resources should be updated with something like:

for dpi in mdpi hdpi xhdpi xxhdpi xxxhdpi; do
  sed -i '/TARGET_RECOVERY_DENSITY/d' device/halium/halium_arm64/BoardConfig.mk
  echo "TARGET_RECOVERY_DENSITY := $dpi" >> device/halium/halium_arm64/BoardConfig.mk
  make recoveryramdisk -j$(nproc)
  diff -r bootable/recovery/res-$dpi/images/ out/target/product/halium_arm64/recovery/root/res/images/
done

Once finalized https://github.com/JamiKettunen/halium_bootable_recovery/tree/halium-16.0 should be imported to https://github.com/ubports/halium_bootable_recovery before merging this