Export epa_at_company_level() and insert_row_with_na_in_risk_category()

[kalashsinghal]

Relates to issue

Dear @maurolepore,

I have to use the epa_at_company_level() and insert_row_with_na_in_risk_category() to assign risk categories to transition risk scores at company level. I will export this function to tiltIndicatorAfter. Please review! Thanks!

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[maurolepore]

LGTM.