Improve notebook rendering jitter

[roblourens]

Things to look into

• Can the viewmodel on the webview side be smarter and anticipate layout changes?
• How long do layouts on both sides take?
• Are sending messages slow?

[vscode-triage-bot]

Pinging notebook topic followers: @claudiaregio @rchiodo @greazer @DonJayamanne @jilljac @IanMatthewHuff

[roblourens]

I have a stash with a bunch of changes that shift some things around but do not really make the user perception better. Fixing the layout too early is basically just as bad as fixing it too late. Let's talk about this @rebornix and you can help me figure out whether any of this can go anywhere.

[rebornix]

@roblourens yup, let's meet some time to discuss them. Maybe with little bit tweaks your changes can improve the layout by a lot.