Allow Plugins to request additional information

[teddyrendahl]

Expected Behavior

There may be use cases where there is information that is needed by multiple Plugins i.e experiment number. In the current schema, this info would have to be duplicated in the YAML file.

Possible Solution

Add an extra class attribute to the BasePlugin called extraneous. This would point to other information in the YAML file that may not be underneath the Plugin explicitly. Then in load_conf.py the extraneous list is checked any additional information needed is added to the info dictionary directly.
For example

YAML file

experiment_no : LJ001

happi:
         ...

Happi Plugin

class Plugin
     name = 'happi'
     extraneous = ['experiment_no']

[ZLLentz]

An even simpler implementation might be to not require an extraneous argument at all, and let all plugins reference the original yaml dictionary. Solid idea.