Wildfire update

[Vedant1]

• created get_abstractions and update_abstractions functions in core.py for user to access the abstraction after using a plugin reader -- useful for existing examples
• updated csv reader/writer to use abstraction not pass through functions
• commented out several pass through functions in sqlite.py and file_reader.py
• updated test_sqlite.py to use newer sqlite functions -- no pass throughs
• updated all plugin readers to handle mismatched columns from several data files in same ingest (ex: results.toml and results1.toml)
• updated sqlite to handle mismatched columns for same table from different ingests to the sqlite db
• moved core functions around so plugin readers called when loaded, and only plugin writers require transload()
• no more transload lock anymore
• specified which function produces an error in error messages -- for user clarity
• updated wildfire and pennant examples to use DSI abstraction layer and new core functions/workflow
• updated examples.rst to use correct sqlite functions and updated pennant example
• updated dsi_units table in sqlite db write and read to separate col_name and units into two columns not one