[CI:DOCS] Add a hello world image to quay.io

[NO NEW TESTS NEEDED]

This commit describes how to run the quay.io/podman/hello
image.  It also contains the files necessary to build that
image localy, and a README.md explaining the image and how
to build it.

Signed-off-by: tomsweeneyredhat <tsweeney@redhat.com>

contrib/helloimage/Containerfile

@@ -0,0 +1,8 @@
+FROM registry.access.redhat.com/ubi8-micro:latest
+
+LABEL maintainer="Podman Maintainers"
+LABEL artist="Máirín Ní Ḋuḃṫaiġ, Twitter:@mairin"
+WORKDIR /tmp
+
+COPY podman_hello_world.bash .
+ENTRYPOINT ./podman_hello_world.bash

contrib/helloimage/README.md

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+![PODMAN logo](../../logo/podman-logo-source.svg)
+
+# Podman Hello World image
+
+## Overview
+
+This directory contains the Containerfile and bash script necessary to create the
+"hello" podman image housed on quay.io under the Podman account in a public
+repository.  The image is public and can be pulled without credentials.
+
+Using this image is helpful to:
+
+ * Prove that basic Podman operations are working on the host.
+ * Shows that the image was pulled from the quay.io container registry.
+ * Container creation was successfuly accomplished. (`podman ps -a`)
+ * The created container was able to stream output to your terminal.
+
+## Directory Contents
+
+The contents of this directory contain:
+ * ./Containerfile
+ * ./podman_hello_world.bash
+
+## Sample Usage
+
+To simply run the image:
+
+```
+podman run quay.io/podman/hello
+
+! ... Hello Podman World ...!
+
+         .--"--.
+       / -     - \
+      / (O)   (O) \
+   ~~~| -=(,Y,)=- |
+    .---. /`  \   |~~
+ ~/  o  o \~~~~.----. ~~
+  | =(X)= |~  / (O (O) \
+   ~~~~~~~  ~| =(Y_)=-  |
+  ~~~~    ~~~|   U      |~~
+
+Project:   https://github.com/containers/podman
+Website:   https://podman.io
+Documents: https://docs.podman.io
+Twitter:   @Podman_io
+```
+To build the image yourself, copy the files from this directory into
+a local directory and issue these commands:
+
+```
+chmod 755 ./podman_hello_world.bash
+podman build -t myhello .
+podman run myhello
+```

contrib/helloimage/podman_hello_world.bash

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+#!/bin/sh
+###
+#  ASCII art by the incomparable Máirín Duffy,
+#  duffy@redhat.com, Twitter: @mairin
+#  January 2022
+###
+echo "                             "
+echo "! ... Hello Podman World ...!"
+echo "                             "
+echo "         .--\"--.            "
+echo "       / -     - \\          "
+echo "      / (O)   (O) \\         "
+echo "   ~~~| -=(,Y,)=- |          "
+echo "    .---. /\`  \\   |~~      "
+echo " ~/  o  o \\~~~~.----. ~~    "
+echo "  | =(X)= |~  / (O (O) \\    "
+echo "   ~~~~~~~  ~| =(Y_)=-  |    "
+echo "  ~~~~    ~~~|   U      |~~  "
+echo ""
+echo "Project:   https://github.com/containers/podman"
+echo "Website:   https://podman.io"
+echo "Documents: https://docs.podman.io"
+echo "Twitter:   @Podman_io"