Show multiple embryos in one Blender window

[maarzt]

User Story

A user would like to open two mastodon datasets, an visualize both in the same Blender window.

Notes

Acceptance criteria

• multiple embryos can be visualized in one blender window

TODOs

[ ] always use the same port for Blender.
[ ] only start a new instance of Blender if there is no existing on.
[ ] make sure a second ViewService is created.
[ ] In Blender add a log message when a view service is created / closed.
[ ] Write some demo code that connects to ViewService clients to Blender
[ ] Improve python implementation to handle two embryos:

• Challanges, a second "ManySpheres" object needs to be created
• Changes of the active object must be