Wishlist: remove file in favor of issue tracker

Remove the 'Wishlist.md' file. The first two items in the list (custom root
directory for repository storage and tracing) have been added to the
repository issue tracker ([1] & [2], respectively). The last (HTTPS web
server support) was added in 5377d04 (web-server: capture and use web server
options, 2023-01-26) and its immediately preceding commits [3].

[1] #25
[2] #22
[3] #10

Signed-off-by: Victoria Dye <[email protected]>