Add Example content of Teaser-Slider Block

[iRohitSingh]

Fix #kitconcept/volto-light-theme#402

[iRohitSingh]

[davisagli]

Please stop. The old plone.distribution import/export format makes this impossible to review. There are too many changed lines to tell whether it is only making the intended change, or also other changes.

@iFlameing previously worked on this in #33 and #34 which had the same problem.

I asked for us to switch to the new plone.exportimport format because it puts each content item in a separate file. That conversion is in progress in #36 but needs more work. (I know Alok asked for help with this -- sorry I didn't find time to help yet. Maybe @ericof can.)

We need to finish switching to plone.exportimport before we try to fix anything in the actual content. Otherwise we'll likely break something each time we fix something else. /cc @sneridagh @tisto

[tisto]

@davisagli thank you for brining this up! Then we should indeed first solve this problem properly before moving on.