Completely silent updates

[RedDragonWebDesign]

An option for completely silent and automatic VS Code updates. Instead of needing to click a bunch of popups in the bottom right corner.

• For the first popup that says "update is available", automatically download and install the update.
• For the second popup that says "restart visual studio code to apply the latest update", automatically assume "later". When the user restarts VS Code, the update will install.
• Don't pop up the release notes in a new tab after updating.

When opening a new window, prevent these popups as well, which tend to pop up again every time you open a new window.

Trigger this behavior by selecting Settings -> Update: Mode > silent and automatic.

[matkoniecz]

duplicate of #9539 found by https://github.com/microsoft/vscode/issues?q=silent+updates+is%3Aopen

[gjsjohnmurray]

/duplicate - thanks @matkoniecz