feat(Docker): allow custom certificates for fastapi/nginx

Now, when a `./cache/production.{cert,key}.pem` pair is found, it is
used in place of any certificates generated by the `ca` service.
This allows users to customize the certificate that the FastAPI
ASGI server uses as well as the front-end nginx certificates.

Optional:

- ./cache/production.cert.pem
- ./cache/production.key.pem

Fallback:

- ./cache/localhost.cert.pem + ./cache/root.ca.pem (chain)
- ./cache/localhost.key.pem

Signed-off-by: Kevin Morris <kevr@0cost.org>

docker/scripts/run-fastapi.sh

@@ -1,17 +1,29 @@
 #!/bin/bash
 
+CERT=/cache/localhost.cert.pem
+KEY=/cache/localhost.key.pem
+
+# If production.{cert,key}.pem exists, prefer them. This allows
+# user customization of the certificates that FastAPI uses.
+if [ -f /cache/production.cert.pem ]; then
+    CERT=/cache/production.cert.pem
+fi
+if [ -f /cache/production.key.pem ]; then
+    KEY=/cache/production.key.pem
+fi
+
 if [ "$1" == "uvicorn" ] || [ "$1" == "" ]; then
     exec uvicorn --reload \
-        --ssl-certfile /cache/localhost.cert.pem \
-        --ssl-keyfile /cache/localhost.key.pem \
+        --ssl-certfile "$CERT" \
+        --ssl-keyfile "$KEY" \
         --log-config /docker/logging.conf \
         --host "0.0.0.0" \
         --port 8000 \
         aurweb.asgi:app
 else
     exec hypercorn --reload \
-        --certfile /cache/localhost.cert.pem \
-        --keyfile /cache/localhost.key.pem \
+        --certfile "$CERT" \
+        --keyfile "$KEY" \
         --log-config /docker/logging.conf \
         -b "0.0.0.0:8000" \
         aurweb.asgi:app