Listing: Display Spaces overview

[exalate-issue-sync]

Userstory

• we need a SDK beforehand -> bkulmann

As a user who had been added to one or more spaces, I want to see an overview of my spaces to that i can enter the space I was looking for.

As Marketing or Sales its useful for me to show a screenshot / demo of the "Spaces overview" so that i have a "visual support" to explain the advantages of ocis.

Acceptance criteria

• assumption: we have a function to list spaces
• Title: Spaces (hardcoded)
• Description Text: (hardcoded)
• no context menu for this story, because we dont have "details" yet
• Gridview directly in web, no ODS Component
• Spaces are implemented as a dedicated App (no extra repo);

List view

• not part in this story, comes later