By Maria Tsvetkova KYIV (Reuters) -The Russian and Ukrainian governments on Friday signalled an openness to negotiations even as authorities in Kyiv urged citizens to help defend the capital from advancing Russian forces in the worst European security crisis in decades. Ukraine and Russia are discussing a place and time for talks, Ukrainian President Volodymyr Zelenskiy’s spokesman Sergii Nykyforov said on social media. The Kremlin said earlier on Friday it had offered to meet with Ukrainian officials in the Belarusian capital Minsk, but that Ukraine had instead proposed Warsaw as a venue, res…