Automate functional test for shared links

[LeeDr]

We need automated tests for;

• the regular iframe code fragments on visualizations
• the shortened iframe code fragments on visualizations
• the regular iframe code fragments on dashboard
• the shortened iframe code fragments on dashboard
• the regular share link on visualizations
• the shortened share link on visualizations
• the regular share link on dashboard
• the shortened share link on dashboard

For the iframe code, we could just check that we got the exact right string, or (more complicated) we could build an html file, open it, and check for content.

[epixa]

@LeeDr Is there any chance of this getting in for 4.5 or should we remove that label?

[LeeDr]

There are tests for Shared Links in the Discover tab in master and 4.x (4.5). Moving the rest of this to master (5.0).