docs(openchallenges): create infrastructure diagram

[tschaffter]

Closes #1553

[!NOTE]
This PR targets the branch drawio.

[!TIP]
New diagrams must be submitted from fork branches created from upstream/drawio.

[!TIP] If we decide to adopt Draw.io, it would be nice to find a GitHub app or create a workflow that renders a PNG from the draw.io file(s) and post them to the PR thread.

Changelog

• create the branch drawio
• add the diagram of the infrastructure of OpenChallenges

Notes

• The link to the diagram can be created by concatenating https://draw.io/#U and the link to the raw .drawio file, e.g. https://draw.io/#Uhttps://raw.githubusercontent.com/Sage-Bionetworks/sage-monorepo/26d915a681e599015329a37b5ef5ffc273a2339a/diagrams/openchallenges/openchallenges-infra.drawio
• Containers have a checkbox to prevent their children to be resized. However, containers are often a group of elements like a border and title and disabling the resize also applies to them, which may not be the desired behavior. A solution is to select the container (group), edit its style and add ;recursiveResize=0 (see this article).

Preview

Open the diagram in Draw.io