Proposed-by: Nicolas George
Ref: https://curl.se/mail/archive-2024-09/0003.html
Closes #14964
9. IMAP
9.1 Enhanced capability support
+ 9.2 upload unread
10. LDAP
10.1 SASL based authentication mechanisms
Add the ability, for an application that uses libcurl, to obtain the list of
capabilities returned from the CAPABILITY command.
+9.2 upload unread
+
+ Uploads over IMAP currently always set the email as "read" (or "seen"). It
+ would be good to offer a way for users to select for uploads to remain
+ unread.
+
10. LDAP
10.1 SASL based authentication mechanisms