Add setting to determine console focus-switching behavior when scripts are executed

[daviwil]

In the 0.10.1 update, we changed the default behavior of script execution actions (F5/F8) to not cause focus to automatically switch to the integrated console. Due to accessibility requirements, we must change this behavior back so that the focus always goes to the console by default. To allow the user to control this behavior to their preference, we'll add the following setting:

"powershell.integratedConsole.focusConsoleOnExecute": true

This can be set to false to disable the default behavior.