[ALU,ALUControl,MIPS,OutputControl] Implemented branch istructions (beq, bne, slt)

[ALU]
- Added numeric_std library
- Added Zero output for branch result
- Implemented branch operations (equal and not equal) and slt result
[AluControl]
- Added 1 more bit to ALUOp
- Mapped new branch operations
[MIPS]
- Updated ALU and ALUControl declarations and statements
- Added new MUXBranch and FA_Branch
- New routing signals
[ OutputControl]
- New branch control signal and relative switch case
- Mapped new ALUOp for branch
[Registers,InstructionMemory]
- Edited for testing functionality