Replace react-sizes with custom implementation

[iduuck]

Motivation

When using react-sizes in conjunction with a server-side mode, we are experiencing a flicker of the screen on either mobile or desktop (depending on the server-side configuration for sizes)

Concept

The concept is fairly simple: We are having a Context's Provider for the current size of the window, which is automatically updated through the window.addEventListener('scroll') event listener.

The initial value should be the window width, when the provider is initialized.

Open Questions

• Will we support Mobx-State-Tree?
• What will happen on server-side rendering?
• Do we need to have a document listener?