Add support for arm64 and armhf architectures

[Pierre Equoy]

Currently, qabro is only available on amd64.

It should be made available also for arm64 and armhf architecture for projects needing this.

[Pierre Equoy (pieq)]

Following a comment by Ogra on the snapcraft forum [1], I made some changes in the snapcraft.yaml file and the snap now builds properly for armhf and arm64:

https://code.launchpad.net/~pieq/+snap/qabro-pieq/+build/220499
https://code.launchpad.net/~pieq/+snap/qabro-pieq/+build/220500

I asked Kristin to check if it worked properly on her ARM device and if it does, I'll push my changes and make a 0.3 release.

[Pierre Equoy (pieq)]

[1] https://forum.snapcraft.io/t/errors-when-trying-to-build-snap-package-for-arm-architecture-using-launchpad-build-infrastructure/5305

[Pierre Equoy (pieq)]

Snap doesn't work on armhf:

$ sudo qabro
/usr/bin/env: relocation error: /snap/qabro/x1/lib/arm-linux-gnueabihf/libc.so.6: symbol __tunable_get_val, version GLIBC_PRIVATE not defined in file ld-linux-armhf.so.3 with link time reference

[Pierre Equoy (pieq)]

After fixing snapcraft.yaml, the build is passed and it was confirmed working by Kristin:

<kristinchuang> ePierre: armhf qabro working!
<kristinchuang> Tried filing a bug as well, worked too (though I had to copy the LP authentication URL to a browser and grant access manually)