Move out workshops generation

[marcingrzejszczak]

We're unable to maintain the workshops in its current form. The workshop documentation needs updating, polishing and the attention that we're currently unable to provide.

What we would like to achieve is:

• Find a new home for the workshops
• Remove the special comments from the samples code
• Remove the gradle tasks to generate the documentation
• Remove the workshops documentation from the repository

If you're interested in maintaining the workshops - please comment on this issue.

[marcingrzejszczak]

The workshop generation got removed in 75d347a. The last version is available under the 3.0.x branch in the docs module