Update style for session request

Move styles to external file.
Make errors red.
Improve positioning of logo,
page is narrow because it is embedded in hisparc.nl.
Simpler getting of current year.
Update html pages to be valid HTML5

Update doctype to `html`.
Update meta tag used to specify utf-8 to use the new charset attribute.
Replace `/>` by `>`, void elements should not be closed; br, link,
input.
Remove `type="text/javascript"` from script tags, javascript is the
default type.
Remove unused wizard form and admin template
Invalid html to put <ul> in a <p>