refactor: remove ratelimiting functionality,

add on-demand global / per-domain ddos protection enabling
add automatic redirect from captcha page back to the requested source
prettify the captcha page

src/cli/ddos_cli.sh

@@ -0,0 +1,27 @@
+#!/usr/bin/env bash
+
+_help() {
+/bin/cat <<EOF
+Usage: $0 <command> [options]
+
+Show help screen and exit.
+
+optional arguments:
+  -h, --help                 show this help message and exit
+
+Commands:
+  Global management:
+  $0 global status           Show status of global server ddos mode.
+  $0 global enable           Enable global ddos mode.
+  $0 global disable          Disable global ddos mode.
+
+  Domain management:
+  $0 domain list             List all domains with ddos mode on.
+  $0 domain status <domain>  Get ddos mode status for a domain.
+  $0 domain add <domain>     Enable ddos mode for a domain.
+  $0 domain del <domain>     Disable ddos mode for a domain.
+EOF
+}
+if ! [[ ${@} ]]; then
+  _help
+fi