[FEATURE] Filter by piece promotions

[rayyaw]

See the title. It would be nice if we could filter games by bishop/knight/rook promotions individually rather than having only the single "underpromotion" option.

[agadmator-library]

I consider current page state as feature complete and I will spend some time on improving code quality. I may add that after all the changes it will bring.
There are only 12 videos showing games with underpromotion and I'm not sure this filter is in high demand.

For now I'll leave issue as open because:
a) I may implement it in future
b) someone else can contribute working filter