Improve console channel argument handling

[nicolasbotanic]

Implement argparse.ArgumentParser to set individually all arguments needed for the python script.

Add chatbotengine and update userid, botid and orgid to be optional.

• chatbotengine: it will set/override chatbotengine value on the .Bot object
• userid: default should be a string with the prefix consoleanon and an alphanumeric secuence of 14 chars
• botid: default should be None. When botid is None the script, obviously, should not try to retrieve any bot from the database. Instead it should define a .Bot object at runtime (no database involved, just a variable) with the defined engine from the argument 'chatbotengine'. In this case there will be no conversation flow so any attemp to talk to the bot will raise an exception from the chatbot engine. But you can run commands like :variables and :df2 on dotflow2 chatbot engine
• orgid: this id is not supported yet, so it can be set by default as 1