Add translation strings

gui/lang-en.json

@@ -38,6 +38,7 @@
    "Idle": "Idle",
    "Ignore Permissions": "Ignore Permissions",
    "Keep Versions": "Keep Versions",
+   "Last seen": "Last seen",
    "Latest Release": "Latest Release",
    "Local Discovery": "Local Discovery",
    "Local Discovery Port": "Local Discovery Port",
@@ -46,6 +47,7 @@
    "Max File Change Rate (KiB/s)": "Max File Change Rate (KiB/s)",
    "Max Outstanding Requests": "Max Outstanding Requests",
    "Maximum Age": "Maximum Age",
+   "Never": "Never",
    "No": "No",
    "No File Versioning": "No File Versioning",
    "Node ID": "Node ID",