Grind exits: pop-out strength slider

A Pop-out strength setting (10-100%, kept) scales the sideways speed of
trigger-set grind exits, for rails next to a wall, where the full exit
carries the skater into it. 100% is the default and exactly the previous
behaviour.

- ReSkate menu: a slider in the GRIND EXITS card, sent when it is let go,
  in steps of 5.
- skate.'s Mod Options and the tools menu: a row stepping 100 / 75 / 50 /
  25%.
- Console: grindexit strength <10-100>; kept in control.txt with the
  other grind exit settings.
- Below 100%, an exit the game was already sending toward the chosen side
  is scaled too, so the setting applies to every trigger-set exit.

Runtime/client_tick.cpp

@@ -962,7 +962,8 @@ void update_model(std::uintptr_t client, TickState& frame) {
     model.board_break = {dingosdk::board_break::available(), dingosdk::board_break::enabled(), !breakable_deck.empty(),
                          dingosdk::board_break::deck_label(breakable_deck)};
     model.grind_exit = {dingosdk::grind_exit_control::available(), dingosdk::grind_exit_control::enabled(),
-                        dingosdk::grind_exit_control::toe_heel(), dingosdk::grind_exit_control::stance()};
+                        dingosdk::grind_exit_control::toe_heel(), dingosdk::grind_exit_control::stance(),
+                        dingosdk::grind_exit_control::strength()};
     model.bindings = dingosdk::local_profile_controller_bindings();
     model.parks = dingosdk::local_profile_parks();
     model.world = dingosdk::local_profile_world_layers();