Improve stage and control layout with flexbox

[lucasnetau]

• Stage and control layout moved from floats to flexbox
• Overflow-wrap implements for text to ensure encapsulation in the stage Fixes If i give large Text for header component in my form builder, UI is getting disrupted. There is no way to limit the length as header component does not p #1524
• Remove $(window).scroll handler with flex sticky CSS

[kevinchappell]

awesome. originally the sticky controls was using javascript to ensure the controls were sticky to the parent container and i think handle some changes on resize. i'm glad this can be done with pure css now!

[github-actions]

🎉 This PR is included in version 3.19.4 🎉

The release is available on:

• npm package (@latest dist-tag)
• GitHub release

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