For the marinade: In a pint-sized mason jar, combine the olive oil, soy sauce, garlic, brown sugar, lemon juice, Dijon mustard, thyme, salt and black pepper. Cover and shake well to combine. Use immediately or store in the refrigerator for up to 4 days before use. For the grilled chicken: Place the chicken in a zip-top gallon bag.  Add all of the marinade, seal the bag and refrigerate for 30 minutes (or up to 4 hours).  Meanwhile, pre-heat one side of the grill to medium heat, around 350°, and leave the other side unlit. Oil the grill grates well.  Remove the chicken from the marinade and pat dry with paper towels. Discard the remaining marinade. Place the chicken skin-side down over the lit side of the grill. Cover and cook until grill marks appear and the chicken easily releases, 6 to 8 minutes.  Flip the chicken and transfer it to the unlit side of the grill. Cover and cook until the internal temperature reads 165˚, 35 to 45 minutes more (depending on the size of your chicken pieces). Let rest for 5 minutes, then serve immediately.