luci-app-banip: new button "Apply & Restart"

* Many changes to the user interface require a banIP restart, e.g. to restructure the underlying nft rule set. In this case, “Apply & Restart” saves the user an unnecessary “Save & Apply” (followed by a banIP reload & restart to obtain the new nft structure.

Signed-off-by: Dirk Brenken <dev@brenken.org>