Retire the previous containerized Agent example from contrib

and update the README.md.

contrib/containerized-pbench/.gitignore

@@ -1,3 +1 @@
 fiotest
-*.tmp
-var_lib_pbench-agent

contrib/containerized-pbench/README.md

@@ -1,10 +1,19 @@
 # Running a Pbench Agent-driven Workload in a Container
-1. Create a workload script (`example-workload.sh` can be used to start)
-   This script performs the invocation of a Pbench Agent workload driver, e.g.
-   `pbench-user-benchmark`, or `pbench-fio`, or `pbench-uperf`.
-2. Setup the local execution environment to be aware of the target Pbench Server
-   `./setup.sh <pbench server host name>:<port number>`
-3. Execute the workload
-   Typically this script performs the necessary setup required for the
-   containerized environment (`example-driver.sh` can be used to start, note
-   that it also moves the results to the Pbench Server).
+
+The Pbench Agent is available for use in a zero-installation scenario
+via containerized execution.  Agent containers are available from
+[quay.io/pbench](https://quay.io/organization/pbench):  there's a
+repository for each distribution (e.g.,
+[pbench-agent-all-centos-9](https://quay.io/repository/pbench/pbench-agent-all-centos-9?tab=tags))
+with tags for each Agent release as well as for "hot builds" for
+each development branch.
+
+The `pbench` script provided here is a wrapper which facilitates
+the invocation of a Pbench Agent command using a containerized
+deployment of the Pbench Agent.  Simply prefix a Pbench Agent
+command line with the path to this script to run it inside a
+container, without needing to install the Agent on the host
+system. (This is easily done by defining a shell alias for it.)
+
+The provided `pbench_demo` script shows the sequence of commands
+which might be used to perform a `fio` benchmark run.

contrib/containerized-pbench/pbench_demo

@@ -12,13 +12,13 @@
 # here because we're not using the default image).
 #-
 shopt -s expand_aliases
-alias pbench=$(git rev-parse --show-toplevel)/contrib/containerized-pbench/pbench
+alias pbench="$(git rev-parse --show-toplevel)"/contrib/containerized-pbench/pbench
 
 FIOTEST=${PWD}/fiotest
 export PB_AGENT_PODMAN_OPTIONS="--pull newer -v ${FIOTEST}:/fiotest:z"
 export PB_AGENT_IMAGE_NAME=quay.io/pbench/pbench-agent-all-fedora-36:main
 
-mkdir -p ${FIOTEST}
+mkdir -p "${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
@@ -28,6 +28,7 @@ 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!
 #-