feat: add initial implementation of osiris, the TLS terminator for Anubis

Signed-off-by: Xe Iaso <me@xeiaso.net>

cmd/osiris/osiris.hcl

@@ -0,0 +1,15 @@
+bind {
+  http    = ":3004"
+  https   = ":3005"
+  metrics = ":9091"
+}
+
+domain "anubis.techaro.lol" {
+  tls {
+    cert = "./internal/config/testdata/tls/selfsigned.crt"
+    key  = "./internal/config/testdata/tls/selfsigned.key"
+  }
+
+  target        = "http://localhost:3000"
+  health_target = "http://localhost:9091/healthz"
+}