don't send requests to specified list of IP CIDRs

this can most definitely be improved but this is a decent attempt.
the only annoying this is i couldn't just use a Vec<IPAddress> which
would have significantly simplified all of this, but serde can't
deserialise it on the config side i guess.

i may find a better way to do this in the future, but this should cover
most areas anyways.

Signed-off-by: strawberry <strawberry@puppygock.gay>

Cargo.toml

@@ -101,6 +101,9 @@ tikv-jemallocator = { version = "0.5.0", features = ["unprefixed_malloc_on_suppo
 lazy_static = "1.4.0"
 async-trait = "0.1.77"
 
+# used for checking if an IP is in specific subnets / CIDR ranges
+ipaddress = "0.1.3"
+
 sd-notify = { version = "0.4.1", optional = true }
 
 [target.'cfg(unix)'.dependencies]