Feat: add ability to set width/height of Container together

[Zyie]

This PR adds the ability to set the width/height of a container in one go which reduces the number of getLocalBounds calls that get made

new Container()
    .setSize(100) // 100, 100
    .setSize(100, 150) // 100, 150
    .setSize({width: 100}) // 100, 100
    .setSize({width: 100, height: 150}) // 100, 150

There is also a getSize() with an optional out property to get the width/height of a container without the additional calls as well

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[GoodBoyDigital]

👍