haproxy-devel, small fixes, fix saving errorfiles from errorfiles tab, fix write 'tcp-request content' before 'use_backend' to avoid warning, fix hint text for a backend without servers

haproxy-devel, small fixes, fix saving errorfiles from errorfiles tab, fix write 'tcp-request content' before 'use_backend' to avoid warning, fix hint text for a backend without servers, stats now give better description if disabled/unavailable, moved templates to their own tab