Added additional functions

[earlng]

Added the additional functions into the output CSV:

• Word count of the impact statement
• Sentence count of the impact statement
• Paper-hash identifier
• Positive-Negative checking (i.e. presence of "positive" or "negative" in the statement)
• Checking if NeurIPS opt-out phrase is included (This work does not present any foreseeable societal consequence)
• Checking if Not Applicable is included