You can count 5Bet shoves using a column expression like this:
sum(if[holdem_hand_player_statistics.enum_p_4bet_action='R' AND holdem_hand_player_statistics.enum_allin='P', 1, 0])
..although this won't be fully accurate as it counts times the player "raised a 5bet" AND "went all-in preflop", but that doesn't actually specify that the all-in was the 5bet. I would imagine unless you're playing hugely deep that a 5bet and an all-in will virtually always be an all-in 5bet.
What would you want the "opportunities" column for this stat to count?
Tutorial: Custom Reports and Statistics