luci-base: rework CBI footer template
luci-base: rework CBI footer template

- Make sure that hitting enter in the form hits the CBI save action and not
  apply or cancel
- Hide action panel if no actions are available
- CLeanup code

Signed-off-by: Jo-Philipp Wich <bd73d35759d75cc215150d1bbc94f1b1078bee01@mein.io>

rogerpueyo/luci,nmav/luci,lbthomsen/openwrt-luci,artynet/luci,chris5560/openwrt-luci,hnyman/luci,tobiaswaldvogel/luci,openwrt-es/openwrt-luci,openwrt/luci,hnyman/luci,tobiaswaldvogel/luci,wongsyrone/luci-1,chris5560/openwrt-luci,artynet/luci,lbthomsen/openwrt-luci,wongsyrone/luci-1,hnyman/luci,rogerpueyo/luci,tobiaswaldvogel/luci,kuoruan/luci,openwrt-es/openwrt-luci,openwrt-es/openwrt-luci,tobiaswaldvogel/luci,rogerpueyo/luci,kuoruan/luci,kuoruan/lede-luci,artynet/luci,openwrt/luci,openwrt-es/openwrt-luci,lbthomsen/openwrt-luci,openwrt/luci,artynet/luci,openwrt-es/openwrt-luci,Noltari/luci,nmav/luci,Noltari/luci,Noltari/luci,openwrt/luci,nmav/luci,kuoruan/luci,artynet/luci,artynet/luci,kuoruan/lede-luci,artynet/luci,openwrt/luci,lbthomsen/openwrt-luci,kuoruan/lede-luci,kuoruan/luci,nmav/luci,chris5560/openwrt-luci,hnyman/luci,wongsyrone/luci-1,Noltari/luci,nmav/luci,artynet/luci,openwrt-es/openwrt-luci,hnyman/luci,tobiaswaldvogel/luci,tobiaswaldvogel/luci,wongsyrone/luci-1,Noltari/luci,rogerpueyo/luci,Noltari/luci,artynet/luci,rogerpueyo/luci,kuoruan/lede-luci,hnyman/luci,kuoruan/luci,kuoruan/luci,openwrt-es/openwrt-luci,openwrt-es/openwrt-luci,rogerpueyo/luci,Noltari/luci,chris5560/openwrt-luci,wongsyrone/luci-1,chris5560/openwrt-luci,openwrt/luci,rogerpueyo/luci,nmav/luci,wongsyrone/luci-1,tobiaswaldvogel/luci,nmav/luci,wongsyrone/luci-1,kuoruan/luci,kuoruan/lede-luci,Noltari/luci,openwrt/luci,chris5560/openwrt-luci,chris5560/openwrt-luci,nmav/luci,hnyman/luci,nmav/luci,Noltari/luci,kuoruan/lede-luci,chris5560/openwrt-luci,lbthomsen/openwrt-luci,kuoruan/luci,kuoruan/lede-luci,kuoruan/lede-luci,lbthomsen/openwrt-luci,tobiaswaldvogel/luci,hnyman/luci,wongsyrone/luci-1,lbthomsen/openwrt-luci,openwrt/luci,lbthomsen/openwrt-luci,rogerpueyo/luci