LP#1783793 - Suspend holds when activation date set in web client angularjs

LP#1783793 - Suspend holds when activation date set in web client angularjs

1. Modify Dates popup changed to not allow picking dates in the past for hold
  activation date both in the date picker, and if typed in manually.  If a
  date in the past is typed in, it is changed to today's date and an alert
  message is displayed.  The date picker just won't allow past days to be
  selected.  The alert message remains until a date in the future is selected.

2. Suspend holds when the activation date is set and saved.

3. Adds a note about the fact that the hold will be suspended when the hold
  activation date is selected for editing.  This makes the behavior clear so
  staff don't have to figure it out by trial and error.

4. Updates several sr-only (Screen Reader Only) labels in the holds date popup
  template that were set to the wrong values.  The file was copied from the hold
  notification popup and the screen reader descriptions were left unchanged from
  those values.

Signed-off-by: Josh Stompro <stompro@stompro.org>