[TF-M] Please review a new design proposal guideline

Hi all,

As part of the documentation improvements, a new design proposal guideline [1] is proposed to replace and simplify the current process. The basic idea is to encourage developers to share their design via mailing list and tech forum, without a well-formatted design document. If developers prefer a document for a new feature, please provide an integration guide/user manual instead.

Please check the details in the patch below. [1] https://review.trustedfirmware.org/c/TF-M/trusted-firmware-m/+/14104

The rendered html version: https://ci-builds.trustedfirmware.org/static-files/KTOoRMhB4VsgNQFkdMgWZcZGn...

Best regards, Hu Ziji