Remove the need for like "F01" from the configuration of fields of the simulated device

[johnspray74]

The simulated device can work these prefixes out for itself.
First character is always F for session data.
Second character is the field number, 0, 1, 2 etc
Third character is a code for the field type 0=float, 1=string, 2=set of values.
We don't need to know the types for the simulated device, at least for now, so just make everything type 1.