Add Piler email archiving support and update scripts

Introduces Piler email archiving with new install and container scripts, and adds metadata for frontend integration. Updates Pixelfed and Postgresus install scripts to improve PHP-FPM pool configuration and streamline build steps.

frontend/public/json/piler.json

@@ -0,0 +1,23 @@
+{
+    "name": "Piler",
+    "slug": "piler",
+    "categories": [
+        "Email",
+        "Archive"
+    ],
+    "date_created": "2025-12-15",
+    "type": "ct",
+    "updateable": true,
+    "privileged": false,
+    "interface_port": "80",
+    "documentation": "https://www.mailpiler.org/",
+    "website": "https://www.mailpiler.org/",
+    "logo": "https://www.mailpiler.org/piler-logo.png",
+    "description": "Piler is a feature rich open source email archiving solution with support for legal hold, deduplication, full text search, and many more features.",
+    "install_methods": [
+        {
+            "type": "default",
+            "script": "ct/piler.sh"
+        }
+    ]
+}