Remove constructors from Safe contract and extensions, which only execute setup function.

[Georgi87]

Since setup function is called from the constructor, and can also be used standalone, the compiler actually generates two copies of this function. These copies are almost the same, the difference is in the way the input argument are read. When setup is called from the constructor, the input arguments are appended at the very end of the transaction data and are access by using CODECOPY. When setup is called standalone, the input arguments are accessed via CALLDATALOAD or CALLDATACOPY. Recommendation - remove call to setup from the GnosisSafe constructor. The master copy setup will require two transactions instead of one, but the benefit is shorter code and easier audit.