SharedWorkspaces using GTPlayground instead of StPlayground

[astares]

If you open a shared workspace from the service that @svenvc provides like this example URL:

http://ws.stfx.eu/6M3DIN9WNU2O

then it uses old removed class "GTPlayground" which is now "StPlayground". So the web application is outdated.

Even when one changes the script from

GTPlayground openUrl: 'http://ws.stfx.eu/6M3DIN9WNU2O'.

to

StPlayground openUrl: 'http://ws.stfx.eu/6M3DIN9WNU2O'.

using it gives an DNU error as there is no #openUrl: in the Pharo 12/13 image:

Also one should now use StPlaygroundPresenter and not GTPlayground or StPlayground

[astares]

As even in Pharo 13 it is still possible to publish workspace/playground content to the @svenvc cloud

we should give it some love and repair it

[astares]

Also it is now StPlaygroundPresenter

We cloud implement a StPlaygroundPresenter(class)>>#openUrl like:

StPlaygroundPresenter openContents: (ZnEasy get: 'http://ws.stfx.eu/6M3DIN9WNU2O') contents