postmarketos-mkinitfs: upgrade to 2.0 (MR 3895)

- Move base files/modules out of package, this package now only provides
  the mkinitfs tool.

- Add all required modules, these were copied over from
  postmarketos-mkinitfs and sorted

- Use new exe name in trigger

- Update triggers to ignore /etc, add /usr/share/mkinitfs. No packages
  should be installing into /etc/mkinitfs/

- Support building/installing docs

- Add vendored deps

- Change trigger path

.ci/shellcheck.sh

@@ -18,8 +18,6 @@ sh_files="
 	./main/osk-sdl/unlock.sh
 	./main/postmarketos-base/rootfs-usr-lib-firmwareload.sh
 	./main/postmarketos-installkernel/installkernel-pmos
-	./main/postmarketos-mkinitfs/init.sh
-	./main/postmarketos-mkinitfs/init_functions.sh
 	./main/postmarketos-initramfs/init.sh
 	./main/postmarketos-initramfs/init_functions.sh
 	./main/postmarketos-mkinitfs-hook-debug-shell/20-debug-shell.sh