Add ExtendedCall to PLCObject as a replacement of RemoteExec and reflect it in eRPC interface.

ExtendedCall is a generic remote procedure call that runtime code can register to and that IDE extensions can call.
For example a fieldbus extension can use ExtendedCall to browse the fieldbus devices connected to the runtime.

<?xml version='1.0' encoding='utf-8'?>
<BeremizRoot xmlns:xsd="http://www.w3.org/2001/XMLSchema" URI_location="PYRO://127.0.0.1:3000">
  <TargetType>
    <Linux/>
  </TargetType>
  <Libraries Enable_SVGHMI_Library="false" Enable_Native_Library="true" Enable_Python_Library="false"/>
</BeremizRoot>