Configure LD_LIBRARY_PATH on snap environment

- Set proper LD_LIBRARY_PATH across the snap
- Fixes missing libceph-common.so on strict

Author: neoaggelos

snap/snapcraft.yaml

@@ -16,6 +16,7 @@ environment:
   PYTHONPATH: $SNAP/usr/lib/python3.8:$SNAP/lib/python3.8/site-packages:$SNAP/usr/lib/python3/dist-packages:$PYTHONPATH
   PATH: $SNAP/usr/bin:$SNAP/bin:$SNAP/usr/sbin:$SNAP/sbin:$PATH
   OPENSSL_CONF: $SNAP/etc/ssl/openssl.cnf
+  LD_LIBRARY_PATH: $SNAP/lib:$SNAP/usr/lib:$SNAP/lib/$SNAPCRAFT_ARCH_TRIPLET:$SNAP/usr/lib/$SNAPCRAFT_ARCH_TRIPLET:$SNAP/usr/lib/$SNAPCRAFT_ARCH_TRIPLET/ceph
 
 parts:
   build-deps: