Adding FIFO tracing capabilities in simulation.

[preusser-amd]

Adding debug capabilities to fifo_gauge and behavioral simulation support for verification.
What will be in this PR:

• FIFO debug logging: fifo_gauge can log consumed data to file + track transaction counts and max fill. Enable with debug_fifo=True in builder config.
• Behavioral RTLSim verification: New verify_rtlsim_behavioral flag passes -define FINN_SIMULATION to xelab, using fifo_gauge (with debug) instead of Q_srl and behavioral DSP models.
• Elementwise consistency: Changed to use ifdef FINN_SIMULATION pattern like MVU/LayerNorm.