Fix Russian airport names

• The proper spelling for airport name with code UUEE is Sheremetyevo Airport, not Sheremet'ye Airport: https://en.wikipedia.org/wiki/Sheremetyevo_International_Airport
• St. Peterburg is a misspelled name of the Russian city Saint Petersburg(https://en.wikipedia.org/wiki/Saint_Petersburg), for which a city entry already exist (lines 20763-20772). The airport name with code ULLI located in this city is Pulkovo Airport: https://en.wikipedia.org/wiki/Pulkovo_Airport