related to #17108 #26484

fixes #30698

This update allows VS Code users to define the desired extensions directory by means of an environment variable "vscode_config_ext", instead of having to rely on the command-line arguments.  By providing a path to the extensions directory in an environment variable, VS Code is able to have a system or user defined extensions directory that does not require a wrapper script to launch code for the settings to take effect.  This solution is similar to the npm ENV variable solution "npm_config_cache".

This is 1/2 of the solution for providing a portable solution to remove VS Code from the Windows roaming profile.

Added --noGettingStarted flag to disable 'Getting Started' page from opening when such provided. Implements #26386.

Part of #329

fixes #20567

fixes #16836

This allows shift+click/middle+click/num+super Windows and Unity shortcuts to
work as expected while not changing regular launch behavior.

Part of #48

Revert "reuse telemetry info when getting common http headers, will likely make use not spawn a process which saves at least 10ms,  #17108"

This reverts commit 8a41bdb7.

reuse telemetry info when getting common http headers, will likely make use not spawn a process which saves at least 10ms,  #17108