Show system apps in the list

[rymsha]

For security reasons it would be better to show system apps in the list, maybe hide them with checkbox or something,
Current problem is - it is super easy for an app to appear as "system" and be hidden from the list.

Also see enonic/xp#6146

[sigdestad]

Lets do it, but list these apps with a small cog icon like we do with system principals. Also need the show/hide filter button

[alansemenov]

Approved :)

[alansemenov]

We will show the system apps with "cog" icon over. It won't be possible to stop or uninstall them.