New ISO names

[zeha]

grml-zeha-daily20231201build22testing-amd64.iso
grml-full-pre2024.12rc1-amd64.iso
grml-full-daily20241201build25unstable-arm64.iso
grml-full-daily20241201build25unstable-amd64.iso
grml-full-daily20240201build25unstable-arm64.iso
grml-full-daily20240201build25unstable-amd64.iso
grml-full-daily20231201build22testing-amd64.iso
grml-full-daily20230201build20unstable-amd64.iso
grml-full-2024.12-arm64.iso
grml-full-2024.12-amd64.iso
grml-full-2024.02-arm64.iso
grml-full-2024.02-amd64.iso

As decided at Debian BSP2024 @ Conova Salzburg, the new scheme should be:

• 4 components, joined together by "-"
• component 1 is statically "grml"
• component 2 is the flavour (small/full)
• component 3 is the version. Version is either a release version string (format YYYY.MM), or a prerelease version string (format preYYYY.MMrcN), or a daily version string (format dailyYYYYMMDDbuildNN<suite>)
• component 4 is the architecture (= debian arch, either amd64 or arm64)

Bootloader should show the version string in a new place instead of in each line.

For grml2usb mixed ISOs we need to find a solution too.