add optional welcome email for new users

When enabled, an email with the server URL and username will be sent to
created users. Requested in #38.

lang/admin/en-us.json

@@ -98,7 +98,9 @@
         "errorLoadOmbiUsers": "Failed to load ombi users.",
         "errorChangedEmailAddress": "Couldn't change email address of {n}.",
         "errorFailureCheckLogs": "Failed (check console/logs)",
-        "errorPartialFailureCheckLogs": "Partial failure (check console/logs)"
+        "errorPartialFailureCheckLogs": "Partial failure (check console/logs)",
+        "errorUserCreated": "Failed to create user {n}.",
+        "errorSendWelcomeEmail": "Failed to send welcome email (check console/logs)"
     },
 
     "quantityStrings": {

lang/email/en-us.json

@@ -37,5 +37,12 @@
         "toJoin": "To join, follow the below link.",
         "inviteExpiry": "This invite will expire on {n}, at {n}, which is in {n}, so act quick.",
         "linkButton": "Setup your account"
+    },
+    "welcomeEmail": {
+        "title": "Welcome to Jellyfin",
+        "welcome": "Welcome to Jellyfin!",
+        "youCanLoginWith": "You can login with the details below",
+        "jellyfinURL": "URL",
+        "username": "Username"
     }
 }