consensus: proto migration (#4984)

## Description

migrate consensus to protobuf

Closes: #XXX

libs/math/safemath.go

@@ -6,6 +6,7 @@ import (
 )
 
 var ErrOverflowInt32 = errors.New("int32 overflow")
+var ErrOverflowUint8 = errors.New("uint8 overflow")
 
 // SafeAddInt32 adds two int32 integers
 // If there is an overflow this will panic
@@ -39,3 +40,14 @@ func SafeConvertInt32(a int64) int32 {
 	}
 	return int32(a)
 }
+
+// SafeConvertUint8 takes an int64 and checks if it overflows
+// If there is an overflow it returns an error
+func SafeConvertUint8(a int64) (uint8, error) {
+	if a > math.MaxUint8 {
+		return 0, ErrOverflowUint8
+	} else if a < 0 {
+		return 0, ErrOverflowUint8
+	}
+	return uint8(a), nil
+}