Remove pbench-generate-token agent CLI functionality (#3383)

* Remove pbench-generate-token agent CLI functionality

- Since we moved away from internal user management in
  Pbench-server, we can no longer use username and password
  to create new tokens.
- The new functionality to generate long-lasting tokens
  will be available via a new server API call and the dashboard.
- Also removes the unused load-canned-data.sh file.

PBENCH-948

agent/Makefile

@@ -51,7 +51,6 @@ util-scripts = \
 # Scripts based on the Python Click package, which are generated during
 # installation.
 click-scripts = \
-	pbench-generate-token \
 	pbench-cleanup \
 	pbench-clear-results \
 	pbench-clear-tools \

contrib/containerized-pbench/pbench_demo

@@ -20,16 +20,21 @@ export PB_AGENT_IMAGE_NAME=quay.io/pbench/pbench-agent-all-fedora-36:main
 
 mkdir -p ${FIOTEST}
 
+# Before we run the demo, we need a Pbench API key. The key can be an
+# environment variable of PBENCH_API_KEY or need to be supplied to this
+# script as an argument.
+api_key=${1:-${PBENCH_API_KEY}}
+if [[ -z "${api_key}" ]]; then
+  echo "Pbench API key must be provided, either on the command line or via the PBENCH_API_KEY environment variable"
+  exit 2
+fi
 #+
 # Run the demo!
 #-
-pbench pbench-generate-token --output=/var/lib/pbench-agent/.token
 pbench pbench-register-tool-set light
 pbench pbench-list-tools
 pbench pbench-user-benchmark --config example-workload -- \
     fio --directory=/fiotest --name fio_test_file --direct=1 --rw=randread \
         --bs=16k --size=100M --numjobs=8 --time_based --runtime=5s \
         --group_reporting --norandommap
-# Note that the token file location below is evaluated -outside- the container,
-# unlike in the pbench-generate-token command above.
-pbench pbench-results-move --token=$(< /var/tmp/${USER}/pbench-agent/run/.token)
+pbench pbench-results-move --token=${api_key}