Remove welcome project duplicate fix

Clean up welcomeProjectsFixed code - Issue #2823
Keyboard shortcut for open folder
update usage of new Dialogs API: done() does not chain, command handlers should return a promise.
Add ability to create multiple global key handlers that override KeyBindingManager. Refactor dialogs and code hints to use this.
Synchronized the menu sections with the current menus
ShellAPI should expect commands to return undefined or a promise
Change 'global keydown handler' terminology to 'global keydown hook' to clarify that these don't work like ordinary event handlers.
code review comments
Align equals signs
What's a handhookler?
Merge pull request #4110 from adobe/nj/issue-3975

REVIEW ONLY: Add ability to create multiple global key handlers
For #3999, use localized string for search placeholder
For #4033, show 'no extensions matched' instead of 'no extensions installed' when query fails
Merge pull request #4102 from adobe/jasonsanjose/issue-4081

Update usage of new Dialogs API
Tweak top offset so the dialog is fully visible at 1024x640
Center the Install from URL dialog better
Merge pull request #4131 from adobe/nj/extman-bug-fixes

Small extension manager bug fixes
Check for 'N' in save dialog even if focus is on a button
Added clarifying comment
Merge pull request #4134 from adobe/nj/issue-4109

Check for 'N' in save dialog even if focus is on a button