Be it further enacted, That the municipal government provided by this Act shall be known as the "councilmanager government". Pursuant to its provisions and subject only to the limitations imposed by the state constitution and by this Act, all powers of the city shall be vested in an elective council, hereinafter referred to as "the council", which shall enact local legislature, adopt budgets, determine policies, and appoint the city manager, who shall execute the laws and administer the government of the city. All powers of the city shall be exercised in the manner prescribed by this Act, or if the manner be not prescribed, then in such manner as may be prescribed by ordinance.