fix: Switch to space-separated sources.conf format

- Change from colon to space separation to avoid URL parsing issues
- Update sources.conf format: TYPE NAME URL VERSION BUILD_FUNCTION [EXTRA]
- Implement awk-based parsing for reliable field extraction
- Fix firmware package list (remove unavailable linux-firmware-marvell)

initramfs/etc/shadow

@@ -0,0 +1,17 @@
+root:*::0:::::
+bin:!::0:::::
+daemon:!::0:::::
+lp:!::0:::::
+sync:!::0:::::
+shutdown:!::0:::::
+halt:!::0:::::
+mail:!::0:::::
+news:!::0:::::
+uucp:!::0:::::
+cron:!::0:::::
+ftp:!::0:::::
+sshd:!::0:::::
+games:!::0:::::
+ntp:!::0:::::
+guest:!::0:::::
+nobody:!::0:::::