Add GitHub Action for firmware releases

[TokenRat]

Your feature request

It would be nice, if we could automatically release the firmware binary on GitHub. GitHub actions would allow us to compile and push the blob onto GitHub.

Detailed outline of the tasks:

• GitHub workflow called 'release' that reacts on tags with the RegEx ^v\d{4}.[0-9][0-9].[0-9][0-9].*
• Builds the firmware. See the existing 'test' workflow
• Creates a 'Draft Release' on GitHub titled with the tag (which will be e.g. v2024.09.13)
• collects the following files from .pio/build/esp32-s3-devkitc-1 and prefixes each with 'ef28badge-': firmware.bin, bootloader.bin, partitions.bin
• Write a .json file that contains the fields 'name' (always 'Eurofurence official', 'date' (current date), 'version' (the tag) and maybe 'URL', where we can put the 'will-be' url of the download to firmware.bin in.
• Attaches these files to the draft release.

Anyone up for the task?