LP#1855457: make grid headers in Angular admin interfaces sticky

LP#1855457: make grid headers in Angular admin interfaces sticky

Grid headers in Angular admininstration interfaces that use
subclass, or copy from AdminPageComponent are now sticky.

To test
-------
[1] Apply the patch and examine Angular admin pages that are
    are based on AdminPageComponent. A good example is the
    MARC Search/Facet Fields server admin page.
[2] Make the grid display a large number of rows, then scroll
    the page. Verify that the grid header is sticky (i.e.,
    the header remains visible in the viewport).
[3] Verify that the Carousels and Standing Penalties local admin
    grids have stick headers.

Signed-off-by: Galen Charlton <gmc@equinoxinitiative.org>