webstaff: throw a kitchen sink at double-scrollbar issues

webstaff: throw a kitchen sink at double-scrollbar issues

This patch ameliorates, but does not eliminate, a bunch
of cases where double-scrollbars could appear.

[1] Adds iframe-resizer (https://github.com/davidjbradshaw/iframe-resizer, MIT license)
    as an option for automatically adjusting the height of an iframe
    to fit the contents.  This can be enabled by ensuring that
    the page to be embedded brings in

    /js/ui/default/staff/build/js/iframeResizer.contentWindow.min.j

    and adding an 'autoresize' attribute to the egEmbedFrame directive.

    This is now used by the legacy reports page.

[2] Gives a 'min-height' attribute to egEmbedFrame and sets a
    value for Dojo grid interfaces embedded by local and server admistration.
[3] Adds a 'allow-escape' attribute to egEmbedFrame; when set to
    true, adds buttons to allow the user to open the embedded page
    in a new tab.
[4] Removes some extraneous <div>s that were interferring with resizing
    for some grids.

Signed-off-by: Galen Charlton <gmc@esilibrary.com>