Bug 36815: Expose to the UI

Bug 36815: Expose to the UI

This patch adds a modal to preview the sample notices in the UI and
allow replacing the template content with that content of that modal.

Test plan
1) Apply patches and restart plack (Or just use a sandbox)
2) Login to the staff client and navigate to 'Tools > Notices and Slips'
3) 'Edit' a notice.
4) Note the new 'View default' button on some notices where we ship a
   default in the 'sample_notices' file.
5) Click the button to view the sample notice
6) Confirm 'Close' just closes the modal
7) Confirm 'Copy' copies the sample notice into the editor field

Signed-off-by: Emily Lamancusa <emily.lamancusa@montgomerycountymd.gov>
Signed-off-by: Kyle M Hall <kyle@bywatersolutions.com>
Signed-off-by: Katrin Fischer <katrin.fischer@bsz-bw.de>