Categories should be a tag optionally added to applications

[Ads20000]

In GNOME Shell, aside from the Sundry and Utilities app folders, apps are not sorted by categories, and the Main Menu app makes these too prominent. Main Menu should detect when the user is on GNOME Shell and not display by category but instead list all the apps in one section (and not use the sidebar at all). Main Menu should also then display the categories as editable tags in the Properties of each app.

ProblemType: Bug
DistroRelease: Ubuntu 18.04
Package: alacarte 3.11.91-3
ProcVersionSignature: Ubuntu 4.15.0-20.21-generic 4.15.17
Uname: Linux 4.15.0-20-generic x86_64
ApportVersion: 2.20.9-0ubuntu7
Architecture: amd64
CurrentDesktop: communitheme:ubuntu:GNOME
Date: Tue May 15 15:12:35 2018
InstallationDate: Installed on 2017-08-03 (284 days ago)
InstallationMedia: Ubuntu 17.04 "Zesty Zapus" - Release amd64 (20170412)
PackageArchitecture: all
SourcePackage: alacarte
UpgradeStatus: Upgraded to bionic on 2018-04-22 (23 days ago)