Add firmware-rtl8723bt package and Pine wifi and bluetooth firmware
subpackage.
[skip ci]: ollieparanoid will build this MR manually before merging, it
will probably not finish CI within one hour.
This is a followup to !109 (merged). Affected packages:
* device/linux-samsung-p4wifi
* device/linux-sony-tulip
* device/linux-teclast-x80pro
* main/linux-postmarketos-allwinner
* main/linux-postmarketos-mainline
* main/linux-postmarketos-qcom
* main/linux-postmarketos-stable
[skip ci] I have confirmed that all 7 kernels still compile.
* Added linux-postmarketos-allwinner kernel
* Added copy of alpines u-boot package with pine-a64lts support
* Changed postmarketos-mkinitfs to add the plain .dtb file to the boot partition
