Software chunks for ID02 upgrade program

Dahu is a lightweight plugin based framework... ... technically a JSON-RPC server over Tango

• plugin can be class or can be generated from stateless function
• a plugin is executed within a job, each job lives in its own thread.
• plugins have empty constructors plus 4 methods (or more)

• setup allows to set the input parameters. It performs sanitization if needed
• process does the taff
• teardown sets the output and the logging and cleans up if needed
• abort can be used to stop the processing if a plugin is a daemon.

• the job is responsible for serializing on disk the plugin input and output
• jobs can be launched using the tango interface (or other ...)
• plugins have a single input and output.
• input/output are dictionaries where keys are strings and values are JSON-serializable (maybe pickle for numpy arrays?)