Add container templates and installers for apps

Add new ProxmoxVED container templates (ct/*.sh), install scripts (install/*.sh) and metadata (json/*.json) for multiple applications: Akaunting, Blinko, Certimate, Dagu, Gogs, InvoiceShelf, Matomo, Papermark, RSS-Bridge, SolidTime and WhoDB. Each ct script includes update logic and deployment helpers; install scripts handle dependency installation, service creation (systemd), DB setup, and Caddy/PHP/Node/Postgres configuration where applicable. JSON entries provide UI metadata, resource defaults and access ports for each app.

json/akaunting.json

@@ -0,0 +1,40 @@
+{
+    "name": "Akaunting",
+    "slug": "akaunting",
+    "categories": [
+        23
+    ],
+    "date_created": "2026-07-13",
+    "type": "ct",
+    "updateable": true,
+    "privileged": false,
+    "interface_port": 80,
+    "documentation": "https://akaunting.com/hc/docs",
+    "website": "https://akaunting.com/",
+    "logo": "https://cdn.jsdelivr.net/gh/selfhst/icons@main/webp/akaunting.webp",
+    "config_path": "/opt/akaunting/.env",
+    "description": "Akaunting is a free, open-source online accounting software designed for small businesses and freelancers, featuring invoicing, expense tracking, and financial reporting.",
+    "install_methods": [
+        {
+            "type": "default",
+            "script": "ct/akaunting.sh",
+            "resources": {
+                "cpu": 2,
+                "ram": 2048,
+                "hdd": 8,
+                "os": "Debian",
+                "version": "13"
+            }
+        }
+    ],
+    "default_credentials": {
+        "username": null,
+        "password": null
+    },
+    "notes": [
+        {
+            "text": "Complete the setup wizard via the web interface on first access.",
+            "type": "info"
+        }
+    ]
+}