Devtools cloud integration

[T4rk1n]

• Add extra requirements for pip install dash[cloud]
• Add a Plotly Cloud button placeholder when plotly-cloud is not installed.
• Add placeholder plotly cli when plotly-cloud is not installed.
• Fix devtool error toggle button always selected.
• Add devtool component api
  • window.dash_component_api.devtool.DevtoolContext is the react context with value:
    -popup: string the current selected popup, '' if nothing selected.
    • setPopup: (value: string) => void set the current toggled popup menu/
  • window.dash_component_api.devtool.useDevtool to use the context as a react hook.
  • window.dash_component_api.devtool.useDevtoolMenuButtonClassName to get the appropriate className to use for a devtool toggle button.
• Consolidate the dev toolbar styling.