New role slurm-client to install a SLURM "submit-only" node.

This is actually a dependency of the `slurm-master` and `slurm-worker`
roles, which I forgot to commit.

elasticluster/share/playbooks/roles/slurm-client/meta/main.yml

@@ -0,0 +1,5 @@
+# slurm-client/meta/main.yml
+---
+
+dependencies:
+  - { role: slurm-common }

elasticluster/share/playbooks/roles/slurm-client/tasks/main.yml

@@ -0,0 +1,66 @@
+# slurm-client/tasks/main.yml
+---
+
+- name: Install required SLURM packages (Debian/Ubuntu)
+  package:
+    pkg={{item}}
+    state=latest
+  with_items:
+    - libpmi0-dev
+    - libslurm-dev
+    - libslurm-perl
+    - libslurmdb-perl
+    - slurm-client
+    - slurm-drmaa-dev
+    - slurm-wlm-torque
+    - sview
+  when: 'is_debian_8_or_later|bool or is_ubuntu_15_10_or_later|bool'
+
+
+- block:
+  # since all the SLURM binaries are bundled in a single package
+  # `slurm-llnl`, we have to install it and *then* stop all the services
+    - name: Install required SLURM packages (older Debian/Ubuntu)
+      package:
+        pkg={{item}}
+        state=latest
+      with_items:
+        - libpmi0-dev
+        - libslurm-dev
+        - libslurm-perl
+        - libslurmdb-perl
+        - slurm-llnl
+        - slurm-llnl-sview
+        - slurm-llnl-torque
+    - service:
+        name={{item}}
+        enabled=no
+        state=stopped
+      with_items:
+        - slurm-llnl
+  when:
+    'is_debian_or_ubuntu|bool and not (is_debian_8_or_later|bool or is_ubuntu_15_10_or_later|bool)'
+
+
+- block:
+  # since all the SLURM binaries are bundled in a single package
+  # `slurm`, we have to install it and *then* stop all the services
+    - name: Install SLURM packages (RHEL-compatible)
+      package:
+        name={{item}}
+        state=present
+      with_items:
+        - slurm
+        - slurm-devel
+        - slurm-perlapi
+        - slurm-sjobexit
+        - slurm-sjstat
+        - slurm-torque
+    - service:
+        name={{item}}
+        enabled=no
+        state=stopped
+      with_items:
+        - slurmd
+        - slurmctld
+  when: is_rhel_compatible