docs: remove mentions to distributed orchestrator mode

[thbcmlowk]

Issue

Closes FL-1239

Description

Removed mentions to distributed orchestrator mode

Build

documentation/orchestrator/index.html

Related

https://github.com/Substra/orchestrator/pull/319

[linear[bot]]

FL-1239 Clean mentions to the distributed mode in the documentation

[guilhem-barthes]

Should we make an info-bubble in the doc mentioning this mode was available until version x.x.x so people coming from previous blogs / whitepapers won't be lost?

[thbcmlowk]

Looks good, just update the changelog plz :)

Thanks for the heads up. Updated

[thbcmlowk]

Should we make an info-bubble in the doc mentioning this mode was available until version x.x.x so people coming from previous blogs / whitepapers won't be lost?

Great idea, thank you. Updated