LONDON (Reuters) – Britain outlined proposed legislation on Tuesday to unilaterally scrap some post-Brexit trade rules for Northern Ireland, risking a diplomatic crisis and the threat of a trade war with the European Union. The two sides have been trying for months to overcome a deadlock over the Northern Ireland protocol, which sets the trading rules for the British-ruled region that London agreed before it left the EU but now says are unworkable. Below are some of the changes Britain plans to include in the legislation: CHECKS ON GOODS When Britain left the EU, Prime Minister Boris Johnson a…