Little visibility adaptations based on feedback from ADCR2024 conference

[vkush]

• add "Repo4Cat" to the name of root dataverse (to make repo more searchable) and replace "root" with "repo4cat"
• change handle shoulder to "4cat"
• add description text to the root dataverse (some info) and remove welcome banner
• think about copy of mail to sender for "Contact" button requests - via DV or via mail-filter -> issue created.