feat: use github.com/eic/eic-spack as local eic-spack repo

Instead of using the local eic-spack repo, we should use the github eic-spack repo. That centralizes and makes it easier for users to use the same package recipes.

containers/jug/dev.Dockerfile

@@ -84,8 +84,8 @@ ARG EICSPACK_VERSION="$SPACK_VERSION"
 RUN git clone https://github.com/eic/eic-spack.git ${EICSPACK_ROOT}     \
  && git -C ${EICSPACK_ROOT} checkout ${EICSPACK_VERSION}                \
  && if [ -n "${EICSPACK_CHERRYPICKS}" ] ; then                          \
-      git -C ${EICSPACK_ROOT} cherry-pick -n ${SPACK_CHERRYPICKS} ;     \
-    fi  
+      git -C ${EICSPACK_ROOT} cherry-pick -n ${EICSPACK_CHERRYPICKS} ;  \
+    fi                                                                  \
  && spack repo add --scope site "${EICSPACK_ROOT}"
 
 ## Setup our custom environment