Add recipe for mailtrap/mailtrap-local (#2052)

mailtrap/mailtrap-local/1.0/manifest.json

@@ -0,0 +1,26 @@
+{
+    "docker-compose": {
+        "docker-compose.override.yml": {
+            "services": [
+                "mailtrap-local:",
+                "  image: mailtrap/mailtrap-local",
+                "  # The Symfony CLI detects a mail catcher by container-internal port, and it",
+                "  # recognizes only 1025 for SMTP together with 1080 or 8025 for the web UI.",
+                "  # Mailtrap Local defaults to 3535 and 3550 and binds loopback only, so the",
+                "  # listeners move here and the non-loopback bind is allowed explicitly.",
+                "  command:",
+                "    - --unsafe-non-loopback",
+                "    - --smtp-listen=0.0.0.0:1025",
+                "    - --http-listen=0.0.0.0:8025",
+                "    - --db=/var/lib/mailtrap-local/db.sqlite3",
+                "  ports:",
+                "    - \"1025\"",
+                "    - \"8025\"",
+                "  labels:",
+                "    # The service is not called \"mailer\", so the prefix is set explicitly to",
+                "    # keep the MAILER_* variables Symfony Mailer expects.",
+                "    com.symfony.server.service-prefix: 'mailer'"
+            ]
+        }
+    }
+}

mailtrap/mailtrap-local/1.0/post-install.txt

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+  * A <comment>mailtrap-local</> service was added to your Docker Compose configuration.
+    Start it with <info>docker compose up -d</>.
+
+  * With the Symfony CLI there is nothing else to do. <comment>MAILER_DSN</> is exposed for
+    you, and <info>symfony open:local:webmail</> opens the web UI.
+
+  * Without the Symfony CLI, ask Docker for the published ports. Docker assigns them
+    at random, in the same way as the <comment>symfony/mailer</> catcher service:
+
+      <info>docker compose port mailtrap-local 1025</>   # SMTP, for MAILER_DSN
+      <info>docker compose port mailtrap-local 8025</>   # web UI
+
+    To pin them instead, replace the two entries under <comment>ports:</> with
+    <comment>"3535:1025"</> and <comment>"3550:8025"</>. Those are Mailtrap Local's own defaults.
+
+  * The <comment>symfony/mailer</> recipe adds its own catcher service, called <comment>mailer</>.
+    When both services run, both claim the <comment>MAILER_</> prefix: one becomes
+    <comment>MAILER_DSN</> and the other becomes <comment>MAILER_1_DSN</>. This is decided when the
+    containers are created. Keep the one catcher you want, so that <comment>MAILER_DSN</>
+    always points where you expect.
+
+  * <fg=blue>Read</> the documentation at <comment>https://github.com/mailtrap/mailtrap-local</>