MONTGOMERY, Ala. — Insurgent Roy Moore’s rout of incumbent GOP Sen. Luther Strange in Alabama’s special election Tuesday has senior Republicans bracing for a wave of resource-draining primaries across the map that could undermine their best-laid plans to defeat Democrats in 2018.Moore’s win — over an incumbent who benefited from millions of dollars in spending by a super PAC aligned with Senate Majority Leader Mitch McConnell — is certain to provide fuel for conservative challengers lining up to take on sitting senators in states like Arizona, Nevada, Mississippi.