Enhance `HolidaysTransform`

[alex-hse-repository]

🚀 Feature Request

HolidaysTransform should make it possible to distinct between the holidays

Motivation

Make work with country holidays more flexible

Proposal

1. Add argument add_holiday_names: bool = False -- if True, create the column with the holidays names
2. Add argument separate_holidays: bool = False -- if True, create separate column for each holiday

Test cases

1. Check that new flags works correctly
2. Check that all columns created when new flags are True are added to the list of regressors

Alternatives

No response

Additional context

No response

Checklist

• [ ] I discussed this issue with ETNA Team