Edu/emulator bin

[ed255]

• Implement an Emulator binary to load and emulate an ELF binary from a path.
• Implement a loader for ELF binary following the Risc-V Proxy Kernel memory map.
• Implement the step Emulator function which fetches an instruction and executes it.
• Implement missing emulator instructions: lui, addi, sd, ld, ecall.
• Use debug_assert for checking that imm is the expected value (which would already be guaranteed by a correct decoder)
• Fix jal emulation: missing +4 in the stored pc
• Add a trait to define Emulator Memory, and implement a simple memory map following the Risc-V Proxy Kernel convention.
• Resolve https://github.com/ed255/riscu-jolt/issues/2