Switch CI tests to use outfile and rename envars

Main changes

    - Switch CI tests to use --outfile option in the examples

    - Update relevant CI envars to be prefixed with UNIFYFS_CI...

    - Change number of processes-per-node used by JOB_RUN_COMMAND to
    be 1 by default

    - Update CI testing docs

001-setup.sh

    - Change auto search preference to manual build first, then Spack

100-writeread-tests.sh

    - Update expected line count of output

990-stop-server.sh

    - Fix exit that kills interactive job allocation when running tests
    individually

ci-functions.sh

    - Change unify_run_test() to get resulting output from outfile
    rather than stdout

    - Turn -k (--check) on for all tests except posix. read-posix
    tests fail with this on. Issue coming.

    - Update cleanup_hosts() to skip if PDSH not available

    - Update optional args and remove -v from default args

testing.rst

    - Move CI config variables to their own sub-section

        - Put current high-impact variables in key variables section

        - Add additional variables section for others that are set
        and might be relevant to developers adding/writing tests

    - Updates to add clarity for running tests

    - Reword get_filename() docs for clarity and outfile addition

    - List additional testing helper functions available in
    ci-functions.sh that may be relevant to developers writing/adding
    future tests

.gitlab-ci.yml

@@ -27,21 +27,21 @@ stages:
 .slurm-single-node-template:
   variables:
     JOB_LAUNCH_COMMAND: "srun -N1 -n1"
-    LLNL_SLURM_SCHEDULER_PARAMETERS: "-N 1 -p pbatch -t $UNIT_WALL_TIME -J unifyfs-unit-tests"
+    LLNL_SLURM_SCHEDULER_PARAMETERS: "-N 1 -p $QUEUE -t $UNIT_WALL_TIME -J unifyfs-unit-tests"
 
 .slurm-multi-node-template:
   variables:
-    LLNL_SLURM_SCHEDULER_PARAMETERS: "-N $NNODES -p pbatch -t $INTEG_WALL_TIME -J unifyfs-integ-tests"
+    LLNL_SLURM_SCHEDULER_PARAMETERS: "-N $NNODES -p $QUEUE -t $INTEG_WALL_TIME -J unifyfs-integ-tests"
 
 .lsf-single-node-template:
   variables:
     JOB_LAUNCH_COMMAND: "jsrun -r1 -n1"
-    LLNL_LSF_SCHEDULER_PARAMETERS: "-nnodes 1 -q pbatch -W $UNIT_WALL_TIME -J unifyfs-unit-tests"
+    LLNL_LSF_SCHEDULER_PARAMETERS: "-nnodes 1 -q $QUEUE -W $UNIT_WALL_TIME -J unifyfs-unit-tests"
     SCHEDULER_PARAMETERS: "-nnodes 1 -P $PROJECT_ID -W $UNIT_WALL_TIME -J unifyfs-unit-tests"
 
 .lsf-multi-node-template:
   variables:
-    LLNL_LSF_SCHEDULER_PARAMETERS: "-nnodes $NNODES -stage storage=${STORAGE_SIZE} -q pbatch -W $INTEG_WALL_TIME -J unifyfs-integ-tests"
+    LLNL_LSF_SCHEDULER_PARAMETERS: "-nnodes $NNODES $STAGE_STORAGE -q $QUEUE -W $INTEG_WALL_TIME -J unifyfs-integ-tests"
     SCHEDULER_PARAMETERS: "-nnodes $NNODES -P $PROJECT_ID -W $INTEG_WALL_TIME -J unifyfs-integ-tests"
 
 ##### Job Templates #####