More options in the query string of playground URLs

[martin-henz]

It may be useful to allow for determining some layout features using the query string of the playground URL. Here is an example that would collapse the editor and the side view, only exposing the REPL. The example also requires that the program is run, using the "run=true" option.

With this, we could implement the judging of rune contest entries without having to generate the images on our side.

[remo5000]

TODO

• Height adjustment
• "Run" tag

[martin-henz]

The screenshot is obsolete: Runes are now in a tab on the upper right. One tab for each loaded module. The overall gist of this Issue is still valid: We should have query-string options for running programs, make a Source Academy tab fill the whole browser tab, etc.