Export `epa_at_company_level()` and `insert_row_with_na_in_risk_category()`

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!

TODO

[ ] Link related issue/PR.
[ ] Describe the goal of the PR. Avoid details that are clear in the diff.
[ ] Mark the PR as draft.
[ ] Include a unit test.
[ ] Review your own PR in "Files changed".
[ ] Ensure the PR branch is updated.
[ ] Ensure the checks pass.
[ ] Change the status from draft to ready.
[ ] Polish the PR description to reflect what it ended up doing.
[ ] Polish the PR title as you'd like others to read it from the git log.
[ ] Assign a reviewer.
[ ] Document user-facing changes in the changelog.

2DegreesInvesting / tiltIndicator

Export `epa_at_company_level()` and `insert_row_with_na_in_risk_category()` #795