Add On Screen Button repeats

[MatthewColvin]

Add the ability for a JSON defined button to have a command/action that is ran every x amount of milliseconds when an on screen button is held down.

Will need some

• [] new keys in the json
• [] parsing/action taking for those new keys.

Maybe
{
....
"RepeatActionIntervalMs" : "5000"
"RepeatAction":"some action"
...
}

I think as of today we have actions and commands in the code base. It would probably be good to settle on one.