fix(jusuf): add deps of psmpi operation

Using the ParaStationMPI module pulls in quite some dependencies → let's all specify them as unbuildable external packages.

site-config/jusuf/packages.yaml

 # `spack external find` with                                                                                                                            
 # Currently Loaded Modules:                                                                                                                             
-#   1) Stages/2024 (S)   2) GCCcore/.12.3.0 (H)   3) zlib/.1.2.13 (H)   4) binutils/.2.40 (H)   5) StdEnv/2024   6) spack/0.20.0                        
+#  1) Stages/2024     (S)   5) StdEnv/2024          9) UCX-settings/RC       13) libxml2/.2.11.4    (H)  17) hwloc/2.9.1            (g)
+#  2) GCCcore/.12.3.0 (H)   6) GCC/12.3.0          10) UCX/default      (g)  14) OpenSSL/1.1             18) PMIx/4.2.6
+#  3) zlib/.1.2.13    (H)   7) numactl/2.0.16      11) pscom/.5-default (H)  15) libevent/.2.1.12   (H)  19) MPI-settings/UCX
+#  4) binutils/.2.40  (H)   8) CUDA/12        (g)  12) XZ/.5.4.2        (H)  16) libpciaccess/.0.17 (H)  20) ParaStationMPI/5.9.2-1 (g)
 packages:
   subversion:
     externals:
     - spec: subversion@1.10.2
       prefix: /usr
   cuda:
+    buildable: False
     externals:
-    - spec: cuda@12
+    - spec: cuda@12.2.91
       prefix: /p/software/jusuf/stages/2024/software/CUDA/12/
       modules:
       - Stages/2024
       - CUDA/12
   cudnn:
+    buildable: False
     externals:
     - spec: cudnn@8.9.5.29-12
       prefix: /p/software/jusuf/stages/2024/software/cuDNN/8.9.5.29-CUDA-12/
@@ -23,6 +28,7 @@ packages:
   mpi:
     buildable: False
   mpich:
+    buildable: False
     externals:
     - spec: "mpich@4.1.5%gcc@12.3.0 arch=linux-rocky8-zen2"
       prefix: /p/software/jusuf/stages/2024/software/psmpi/5.9.2-1-GCC-12.3.0-pmi/
@@ -37,10 +43,52 @@ packages:
   llvm:
     variants: ~cuda
   binutils:
+    buildable: False
     externals:
     - spec: binutils@2.40
       prefix: /p/software/jusuf/stages/2024/software/binutils/2.40-GCCcore-12.3.0
   openssl:
+    buildable: False
     externals:
-    - spec: openssl@1.1
+    - spec: openssl@1.1.1k
       prefix: /p/software/jusuf/stages/2024/software/OpenSSL/1.1
+  numactl:
+    buildable: False
+    externals:
+    - spec: numactl@2.0.16
+      prefix: /p/software/jusuf/stages/2024/software/numactl/2.0.16-GCCcore-12.3.0
+  ucx:
+    buildable: False
+    externals:
+    - spec: ucx@1.15.0
+      prefix: /p/software/jusuf/stages/2024/software/UCX/default-GCCcore-12.3.0
+  xz:
+    buildable: False
+    externals:
+    - spec: xz@5.4.2
+      prefix: /p/software/jusuf/stages/2024/software/XZ/5.4.2-GCCcore-12.3.0
+  libxml2:
+    buildable: False
+    externals:
+    - spec: libxml2@2.11.4
+      prefix: /p/software/jusuf/stages/2024/software/libxml2/2.11.4-GCCcore-12.3.0
+  libevent:
+    buildable: False
+    externals:
+    - spec: libevent@2.1.12
+      prefix: /p/software/jusuf/stages/2024/software/libevent/2.1.12-GCCcore-12.3.0
+  libpciaccess:
+    buildable: False
+    externals:
+    - spec: libpciaccess@0.17
+      prefix: /p/software/jusuf/stages/2024/software/libpciaccess/0.17-GCCcore-12.3.0
+  hwloc:
+    buildable: False
+    externals:
+    - spec: hwloc@2.9.1
+      prefix: /p/software/jusuf/stages/2024/software/hwloc/2.9.1-GCCcore-12.3.0
+  pmix:
+    buildable: False
+    externals:
+    - spec: pmix@4.2.6
+      prefix: /p/software/jusuf/stages/2024/software/PMIx/4.2.6-GCCcore-12.3.0