WIP: add predefined ratelimits

files/config/conf.d/ratelimits.conf

+geo $limit {
+	default 1;
+	10.0.0.0/8 0;
+	192.168.0.0/24 0;
+}
+ 
+map $limit $limit_key {
+	0 "";
+	1 $binary_remote_addr;
+}
+ 
+limit_req_zone $limit_key zone=10rps:10m rate=10r/s;
+limit_req_zone $limit_key zone=100rps:10m rate=100r/s;
+limit_req_zone $limit_key zone=1000rps:10m rate=1000r/s;