Update Documentation and manual.md

[micbar]

New updated docs should be ready when we reach Milestone https://github.com/owncloud/data_exporter/milestone/6

@IljaN and me will provide all the information.

[micbar]

@mmattel @settermjd FYI

[mmattel]

I have a proposal:

• Improve and update the official documentation
  this is the one we reference to
• Use the repro documentation to add internal stuff or things which go too deep to be used in the official docs. Link the official doc into the local doc

Benefit:
One place to maintain for each part, clear structure and responsibilities

[micbar]

unassigning myself.