Rename short_title to pwa_short_name

What does this MR do and why?

Renaming appearances short_title attribute to pwa_short_name

Cleans up the renaming of appearances short_title attribute to pwa_short_name

Adapts backend and specs

For context: !104582 (comment 1220205708) and !106979 (comment 1221719043) and !107884 (comment 1223639306)

MR acceptance checklist

This checklist encourages us to confirm any changes have been analyzed to reduce risks in quality, performance, reliability, security, and maintainability.

• I have evaluated the MR acceptance checklist for this MR.

🛠 with ❤ at Siemens