Item12783: first batch of improvements to configure UI

   * Move action buttons and status info to the top: easy to miss at the bottom, and fixed content at the bottom is tricky in the first place
      * This required reworking the "unsaved changes" widget as it broke the HTML
   * Add pretty pictures to (most of) those buttons
   * Get rid of largely useless legend on the welcome page -- all of that is self-explanatory
   * Get rid of visual autocheck cue -- the user will see that autochecking is happening when they change a value
   *


git-svn-id: http://svn.foswiki.org/trunk/core@17343 0b4bb1d4-4e5a-0410-9cc4-b2b747904278