Share batch function to rename processes on the fly

A process in the task console or views console will show a process' name as the name of the template.
In just about every instance we create, we rename the process to something that distinguishes it from all the other processes of the same type.

We do this ourselves via a batch function and the Maestro API, however, for a more generic use case, we can provide a batch function that uses a process variable's value to set the process value.

By setting a process_name process variable to some text, the batch function's execution of maestro_set_process_name handler will set the process to the value of the PV.

This is very specific in utility and functionality such that if you already have a process variable names process_name, and you use this batch function handler, it will set the process name to the PV value.