add test image for complement

This image should satisfy the requirements described in [1]. openssl
commands were copied from [2].

[1]: https://github.com/matrix-org/complement?tab=readme-ov-file#image-requirements
[2]: https://github.com/matrix-org/complement?tab=readme-ov-file#complement-pki

nix/pkgs/complement-grapevine-oci-image/config.toml

@@ -0,0 +1,38 @@
+# this config file is processed with envsubst before being loaded
+
+server_name = "$SERVER_NAME"
+
+allow_registration = true
+
+# complement tests the unauthenticated media endpoints
+serve_media_unauthenticated = true
+
+[server_discovery.client]
+base_url = "https://$SERVER_NAME"
+
+[federation]
+trusted_servers = []
+
+[database]
+backend = "rocksdb"
+path = "/app/db"
+
+[observability.logs]
+filter = "debug,h2=warn,hyper=warn"
+# ansi escapes can make it hard to read the log files in an editor
+colors = false
+
+[tls]
+certs = "/app/grapevine.crt"
+key = "/app/grapevine.key"
+
+[[listen]]
+type = "tcp"
+address = "0.0.0.0"
+port = 8008
+
+[[listen]]
+type = "tcp"
+address = "0.0.0.0"
+port = 8448
+tls = true