README: add compatibility tables for configurations

Changelog: title

The configuration files are only meant to work on
specific combinations of board+OS. These are added
verbatim in order to avoid confusion.

Signed-off-by: Josef Holzmayr <josef.holzmayr@northern.tech>

README.md

@@ -44,10 +44,35 @@ For more detailed information about `mender-convert` please visit the
 [Debian family](https://docs.mender.io/artifacts/debian-family) section in
 [the Mender documentation](https://docs.mender.io/).
 
+## Included configurations
 
-### Prepare image and configuration
+### Core configurations
+
+These configurations are officially supported.
+
+| Configuration | Supported OS / hardware |
+| :------------ | :---------------------- |
+| generic_x86-64_config | Generic x86, 64bit distribtion *use this as a starting point only!*  |
+| raspberrypi0w_config | RaspberryPi 0w, Raspbian 32bit |
+| raspberrypi3_config | RaspberryPi 3, Raspbian 32bit |
+| raspberrypi4_config | RaspberryPi 4, Raspbian 32bit |
+| raspberrypi4_ubuntu_config | RaspberryPi 4, Ubuntu 32bit |
+
+### Contributed configurations
 
-*Only 32bit-Images are supported at the moment!*
+These configurations have been submitted by community contributors.
+
+| Configuration | Supported OS / hardware |
+| :------------ | :---------------------- |
+| beaglebone_black_debian_emmc_config | BeagleBone Black 4GB, Debian 32bit on internal eMMC storage |
+| beaglebone_black_debian_sdcard_config | BeagleBone Black, Debian 32bit on external SD card storage |
+| comfile_pi_config | Comfile Pi, Raspbian 32bit |
+| rockpro64_emmc_config | RockPro64, Debian 32bit on internal eMMC storage |
+| rockpro64_sd_config | BeagleBone Black, Debian 32bit on external SD card storage |
+
+## Example usage: Raspberry Pi 3, Raspbian 32bit
+
+### Prepare image and configuration
 
 The following steps give a quick start using Raspbian. For a more detailed guide,
 especially concerning version compatibilities, please visit [the the corresponding thread](https://hub.mender.io/t/raspberry-pi-3-model-b-b-raspbian/140) on the Mender Hub.