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 being added,
this breaks the original "design". I unfortunately don't have a clue (yet) about quickly adapting the design of the form (like aligning the port field to the right e.g.).

I somehow messed up the index.html view as I played around with copy/paste sections, but I think it only looks bad in the compare, because I didn't change anything apart the <select> and the order of the fields (port field after security field). 

p.s. This is my first commit to GitHub and to OpenSource ever, so please
be gentle :)