Improve UI

* add CSS classes to fields
* use monospace font for field values
* min-width for record content edit field, stretch label and content
  to dialog width
* max-width for record content table cell, explicit (percent) column
  sizes
* text-align: right numbers
* display raw data in cells with $('<span>').text(...)
* add DNSSEC info and masters for slave zones
* add some RR types and disable distinction from address .arpa zone;
  show all types for every field
CSRF tokens and autologin