This option determines if the user can make use of Webmin's poweful RPC calls
feature, which is designed to allow this system to be controlled by a script
or other Webmin server via HTTP. Because the RPC feature does not
respect any module grants or fine-grained access controls, this option should
only be enabled for fully trusted root-equivalent users.
In addition, if the RPC calls only option is selected, the user will not
be able to use the Webmin UI. This is useful for creating a separate login with
a longer password for RPC purposes only, as two-factor authentication cannot be
used when making RPC calls.