Pulldown selection added for IMAP & SMTP security config

As discussed by the main developers of the master branch, two pulldown
boxes have been added with subsequent prefilling of the port fields.

IMAP security "none","ssl","tls"
-> IMAP port  "143","993"

SMTP security "none","ssl","tls"
-> SMTP port "25","465"

There are still massive design problems with the pulldownboxes added,
this breaks the original "design".

p.s. This is my first commit to GitHub and to OpenSource ever, so please
be gentle :)