Disable `editor.quickSuggestions` setting by default

[per1234]

Is your feature request related to a problem? Please describe.
While the auto complete functionality will be extremely useful to advanced users, the low level code it exposes constantly while typing will be confusing and distracting to beginners

Describe the solution you'd like
Disable the editor.quickSuggestions setting by default.
Add a setting to File > Preferences to allow this feature to easily be enabled by those who want it.

Describe any alternative solutions you've considered

Configure auto-complete to be triggered via a keyboard shortcut instead of automatically popping up any time you type anything.

Environment

OS: Windows 10
Version: 2.0.0-beta.2-snapshot.298cc11
Date: 2021-02-15T14:16:52.603Z
CLI Version: 0.16.0 alpha [c977a238]