LONDON (Reuters) -Britain set out its first national food strategy on Monday, focused on increasing domestic output of some produce to boost food security while rejecting a recommendation to tackle obesity with new taxes on salt and sugar in processed food. The government said Russia’s invasion of Ukraine had hit food supplies and caused prices to spike, underlining the need to boost Britain’s home-grown supply of food. The plan will broadly maintain the current level of food produced domestically, while boosting output in some sectors such as horticulture and seafood, it said. Farming will re…