info: Use udev to get the hardware RAM size
libgtop gets the RAM size as is visible to the OS, so the physical RAM size minus all the reserved areas listed at the top of your usual Linux dmesg output.
Use systemd 248's MEMORY_ARRAY_* properties attached to the pseudo-DMI device to get the size of the RAM sticks/chips as the user expects.
Closes: #1540 (closed)