pub draft 17: no /UCD, no zipped

[markusicu]

[182-A4] Action Item for Markus Scherer, PAG: Adjust the deployment of data files for the synchronized standards (UTS10, UTS39, UTS46, UTS51), so that they are published in the same versioned directory in the /Public folder on the website as the UCD data files. For Unicode Version 17.0. [Ref. Section 3.3 of L2/25-012]

• Changing the publication shell scripts for /Public/draft/
• I will later adjust the proposed workflow in PR Workflow: Publish Data #980 for both draft & final. I just wanted to move quickly for alpha. -- FYI @lianghai
• Flatten the structure by removing the intermediate .../UCD/... folder.
• This promotes the version-ReadMe.txt which used to go into /Public/draft/UCD/ to now be the readme in /Public/draft/, just like in the final release it already became /Public/{version}/ReadMe.txt.
• I changed the wording there to be flexible about the set of subfolders, which changes during alpha & beta.
• We no longer write to a zipped/ folder and thus no longer need the zipped-ReadMe.txt.