Added V5 Max ISO

[susch19]

Description

Add the v5 max ISO firmware files. The implementation is based on the v3 max ISO to ANSI differences, so I don't know if all the values are correct, but for now all keys are working when testing matrix on launcher.keychron.com. It's also still detected as the ISO knob version.

Types of Changes

• Core
• Bugfix
• New feature
• Enhancement/optimization
• Keyboard (addition or update)
• Keymap/layout/userspace (addition or update)
• Documentation

Issues Fixed or Closed by This PR

• [Feature Request] V5 Max ISO Layout #297

Checklist

• My code follows the code style of this project: C, Python
• I have read the PR Checklist document and have made the appropriate changes.
• My change requires a change to the documentation.
• I have updated the documentation accordingly.
• I have read the CONTRIBUTING document.
• I have added tests to cover my changes.
• I have tested the changes and verified that they work and don't break anything (as well as I can manage).

[Mhilkos]

The firmware is available as a pre-compile on the keychron website. https://www.keychron.com/pages/firmware-and-json-files-of-the-keychron-qmk-v-and-v-max-series-keyboards
Also, theres VIA json there for download if you scroll down so you can make VIA detect it if you dont want to use the keychron launcher.

[susch19]

The firmware is available as a pre-compile on the keychron website. https://www.keychron.com/pages/firmware-and-json-files-of-the-keychron-qmk-v-and-v-max-series-keyboards

Yeah, but I didn't add the file, but the source code for it, so one can customize it. I guess keychron will most likely add their own source code version later on, but as long as this didn't happen, it is good to have the source code. But you are right, i didn't think to download the via json from the website, so i can at least use the correct via json in this pr

[susch19]

The layout has been added, so this pr is not needed anymore