This Charter shall not be construed as a mere grant of enumerated powers, but shall be construed as a general grant of power and as a limitation of power on the government of the City in the same manner as the Constitution of Texas is construed as a limitation on the powers of the Legislature. Except where expressly prohibited by this Charter, each and every power under Article XI, Section 5, of the Constitution of Texas which it would be competent for the people of the City of Sweeny to grant expressly to the City, shall be construed to be granted to the City by this Charter.