Fix 32/64 bit architecture detection

[DesktopECHO]

To determine if the Debian edition hosting NextCloud is 32 or 64 bit, NCP uses uname -m. This is mostly fine until you have (for example) a kernel reporting aarch64 that is running Debian armhf in a container, whereupon the wheels fall off and scripts break.

As opposed to asking the Kernel, it's more reliable to ask the distro if NextCloud is 32 (armv7l, armv8l) or 64 (aarch64) bit to account for all possible hardware setups.