webui: Some fixes related to SSL generation too

This includes:
  - really set insecure to true when generating certificate (it wasn't
    set in the json)
  - also make the path to certificate and key files disabled
webui: Fix string to be consistent

self-signed, instead of auto-signed.
webui: Set xxlarge class on file type inputs

For text input fields that take large amount of data (like a full file +
path), setting input-xxlarge class helps with getting a proper display
when using bootstrap.