board/common: bundle helpful README in release tarballs

Signed-off-by: Joachim Wiberg <troglobit@gmail.com>

board/common/README.txt

@@ -0,0 +1,130 @@
+Welcome to Infix!
+=================
+
+Nice to meet ❤️ you!  If you are reading this then you have possibly
+just downloaded and unpacked a release build and are curious about how
+to proceed from here.
+
+To test Infix You need a Linux 🐧 system with Qemu or GNS3 installed.
+We recommend Debian based systems, like Ubuntu and Linux Mint.
+
+> For a pain-free experience we recommend enabling CPU virtualization in
+> your BIOS/UEFI, which for many computers is disabled by default.
+
+From this point we assume you have your x86_64/AMD64 based Linux system
+up and running.  Time to start your favorite terminal application! 😃
+
+
+Installing Qemu
+---------------
+
+This README focus on getting you started with Qemu.  From a terminal,
+install (at least) the x86/x86_64 emulator.  The 'virt-manager' is a
+package that helps pull in other dependencies you may need:
+
+    $ sudo apt install qemu-system-x86 virt-manager
+
+That's it.
+
+
+Running Infix in Qemu
+---------------------
+
+Depending on how your Linux installation is set up, the following may
+require being run with superuser privileges, i.e., you may need to
+repend the command with 'sudo'.
+
+    $ ./qemu.sh
+
+You should now see the Infix init system booting up.  When the final
+"Please press Enter to activate this console." is shown, press Enter
+and the login: prompt is displayed.
+
+The default credentials for the demo builds is
+
+    login: admin
+    password: admin
+
+    Infix -- a Network Operating System v24.09.0-rc1 (hvc0)
+    infix-00-00-00 login: admin
+    Password: 
+    .-------.
+    |  . .  | Infix -- a Network Operating System
+    |-. v .-| https://kernelkit.org
+    '-'---'-'
+
+    Run the command 'cli' for interactive OAM
+
+    admin@infix-00-00-00:~$
+
+You're in!  Play around in your sandbox as much as you like, if you
+run into problems or have questions, please see the documentation,
+and don't hesitate to get in touch with us! 😃
+
+ - https://github.com/kernelkit/infix/tree/main/doc
+
+
+Customizing your "Hardware"
+---------------------------
+
+For more Ethernet ports in your emulated system you need to change the
+Qemu configuration used for Infix.  This can be done using a menuconfig
+interface, which requires the following extra package:
+
+    $ sudo apt install kconfig-frontends
+
+We can now enter the configuration:
+
+    $ ./qemu.sh -c
+
+Go down to *Networking*, select *TAP*, now you can change the *Number of
+TAPs*, e.g. to 10.  Exit and save the configuration, then you can start
+Qemu again:
+
+   ./qemu.sh
+
+> Make sure to do a factory reset from the CLI, otherwise you will be
+> stuck with that single interface from before.
+
+
+Errors on Console
+-----------------
+
+If you see the following line printed one or more times, don't panic.
+
+    LABEL=var: Can't lookup blockdev
+
+See the Customizing section above.  To silence the error you need to
+create another writable partition for Infix to store logs, container
+images, etc.  Look for the 'var' keyword, you can adjust the size of
+the partition.
+
+
+Graphical Network Simulator 3 (GNS3)
+------------------------------------
+
+GNS3 is a very powerful front-end to Qemu which takes care of creating
+virtual links between network devices running in Qemu.  This README is
+only link to the material you need.  This directory holds the appliance
+file, .gns3a, that references image files also in this directory, that
+you need to load into GNS3.
+
+The necessary extra packages are available through the offical PPA.  If
+you don't know what a PPA is, read up on that first:
+
+ - https://launchpad.net/~gns3/+archive/ubuntu/ppa
+
+There's a lot of tutorials and guides online, start here:
+
+ - https://docs.gns3.com/docs/
+
+
+About
+-----
+
+Infix is a free, Linux based, immutable Network Operating System (NOS)
+built on Buildroot, and sysrepo.  A powerful mix that ease porting to
+different platforms, simplify long-term maintenance, and provide easy
+management using NETCONF, RESTCONF, or the built-in command line
+interface (CLI) from a console or SSH login.
+

board/common/post-image.sh

@@ -102,3 +102,6 @@ rm -f "$BINARIES_DIR/qemu.cfg"
 CONFIG_="CONFIG_" BR2_CONFIG="$BINARIES_DIR/qemu.cfg" \
        "$O/build/buildroot-config/conf" --olddefconfig "$BINARIES_DIR/Config.in"
 rm -f "$BINARIES_DIR/qemu.cfg.old" "$BINARIES_DIR/.config.old"
+
+# Quick intro for beginners, with links to more information
+cp "$BR2_EXTERNAL_INFIX_PATH/board/common/README.txt" "$BINARIES_DIR/"