Add account deletion with email notification

Select users to delete, then optionally opt to notify the user in an
email with a provided reason.

data/config-base.json

@@ -10,6 +10,7 @@
         "mailgun",
         "smtp",
         "ombi",
+        "deletion",
         "files"
     ],
     "jellyfin": {
@@ -634,6 +635,41 @@
             "description": "API Key. Get this from the first tab in Ombi settings."
         }
     },
+    "deletion": {
+        "order": [
+            "subject",
+            "email_html",
+            "email_text"
+        ],
+        "meta": {
+            "name": "Account Deletion",
+            "description": "Subject/email files for account deletion emails."
+        },
+        "subject": {
+            "name": "Email subject",
+            "required": false,
+            "requires_restart": false,
+            "type": "text",
+            "value": "Your account was deleted - Jellyfin",
+            "description": "Subject of account deletion emails."
+        },
+        "email_html": {
+            "name": "Custom email (HTML)",
+            "required": false,
+            "requires_restart": false,
+            "type": "text",
+            "value": "",
+            "description": "Path to custom email html"
+        },
+        "email_text": {
+            "name": "Custom email (plaintext)",
+            "required": false,
+            "requires_restart": false,
+            "type": "text",
+            "value": "",
+            "description": "Path to custom email in plain text"
+        }
+    },
     "files": {
         "order": [
             "invites",