The Danbury Democratic and Republican Town Committees have endorsed slates of candidates for November.  The Democrats chose Councilman Roberto Alves as their candidate for Mayor.  The Republicans are backing mayoral Chief of Staff Dean Esposito.  Alves could face a primary in September.  Councilman John Esposito III submitted a letter yesterday to City Hall with his intentions to primary.  He has until close of business on August 11th to gather and submit 710 verified signatures from Democratic voters, 5-percent of those registered in the City, to force a September 14th primary.  Political newcomer Sedeaka Lawrence said he aims to do the same. The Connecticut Working Families Party has endorsed Alves.