No way to discern multiple versions of the same app (from different sources)

In the new world there's basically an infinite number of the same application you can have installed at the same time:

- snap
  - multiple different snaps can ship the same application
- libertine
  - you can have multiple containers with the same application
- deb
  - you could have a PPA added that has the same application under a different package name

Today the result is that the app drawer shows all of them, in undefined order. This makes it impossible to know which of them you launch.

=== Proposal 1 ===

In the app drawer, have "badges" for apps that have multiple versions installed, and a drop-down to select between the different versions.

Since we'd be grouping in the app drawer, I'd propose to group elsewhere in the shell (launcher, switcher), with icon badges indicating for each top-level window.

=== Proposal 2 ===

Have all the different versions listed as usual, but have unique badges for those that have multiple versions.

In this case we'd treat all of them as completely separate in the rest of the shell as well.

ProblemType: Bug
DistroRelease: Ubuntu 17.04
Package: unity8 8.15+17.04.20170303.1-0ubuntu1 [origin: LP-PPA-ci-train-ppa-service-2481]
ProcVersionSignature: Ubuntu 4.10.0-9.11-generic 4.10.0
Uname: Linux 4.10.0-9-generic x86_64
NonfreeKernelModules: zfs zunicode zavl zcommon znvpair
ApportVersion: 2.20.4-0ubuntu2
Architecture: amd64
CurrentDesktop: Unity:Unity7
Date: Tue Mar 7 15:15:58 2017
InstallationDate: Installed on 2016-05-06 (304 days ago)
InstallationMedia: Ubuntu 16.04 LTS "Xenial Xerus" - Release amd64 (20160420.1)
SourcePackage: unity8
UpgradeStatus: Upgraded to zesty on 2016-11-22 (105 days ago)