Move email SMTP config to settings page with encrypted password storage; add cryptography dependency

booth_settings.json

@@ -0,0 +1,11 @@
+{
+  "artist": "Trollgorithm",
+  "album": "Theme Booth",
+  "year": "2026",
+  "comment": "Booth song",
+  "smtp_host": "mail.example.com",
+  "smtp_port": "587",
+  "smtp_user": "test@example.com",
+  "smtp_from": "test@example.com",
+  "smtp_pass": "gAAAAABqbn8zm5n1fPOfAAMubFQmfsaCDcE16MFoRMEDPLqlnZIocc2W-qMPSYbFkls6E7aabpqEo3aAGLUsG5TlaWlqpFhWyg=="
+}