feat: docker config for new frontend

docker/Caddyfile

@@ -1,4 +1,11 @@
-http:// {
+# Frontend and API
+http://localhost:80 {
     reverse_proxy /api/* http://rate:5003
     reverse_proxy http://frontend:3000
-}
+}
+
+# prns.cc (profile URL shortener)
+http://localhost:81 {
+    rewrite * /sid{uri}
+    reverse_proxy http://backend:5000
+}

docker/frontend.example.env

@@ -0,0 +1,4 @@
+PUBLIC_LANGUAGE=en
+PUBLIC_BASE_URL=https://pronouns.cc
+PUBLIC_SHORT_URL=https://prns.cc
+PUBLIC_API_BASE=https://pronouns.cc/api