Offhand for bedrock edition and mobile support.

We need an offhand on bedrock edition:

First for keyboard, controler and new mobile control, add an option to have a new offhand botton:

The offhand botton is a bouton that do the right click for the offhand this is useful for exemple if you have a block in you mainhand and another in your offhand, or a shield in the offhand.

Can be custom like every other botton by setting it to a specific botton (by default L1/L/LT) and moving the bouton around (by default on top of the joystick) only if the "offhand bouton" setting is enable.

For hold mobile control (with the circle thing), the "offhand bouton" setting HAVE to be on.

How it work ?:

- For the shield, bow, enderpearl and every items that don't need any aim to use (only when they are in the offhand) just click this new botton.

- For items that need aim like placing blocks or breaking them, the player have to hold the Offhand button with is left hand AND interact like he would do for a mainhand objet. Just stop holding to get back to the mainhand.

Also, you should hide the offhand bouton when the offhand is emptie.