Updated dsi features and deleted old code

[Vedant1]

• deleted old commented out code in several files including pass through functions
• added new language for inserting data into backend (write) and taking data from backend (process) on top of existing put/get
• updated pennant and wildfire examples with this
• new find function in core and backend files to search for a term among all tables, cols and datapoints in a backend. Return object varies depending on where there is a match
• updated core file to set run_flag = False by default
• in core.py, check if backend is a subclass of Filesystem before accessing the filename variable in the backend