[ENH] Server Embedder: switch to new cluster

[PrimozGodec]

Description of changes

We implemented a new cluster in which performance is much better. Some embedders are 10 times faster with the new cluster.

Note: We must merge https://github.com/biolab/orange3/pull/4984 before merging this PR.

Includes

• [X] Code changes
• [ ] Tests
• [ ] Documentation

[PrimozGodec]

It would be nice if a few people in the lab can test this PR

[codecov[bot]]

Codecov Report

Merging #188 (296e8b2) into master (fac17f8) will not change coverage. The diff coverage is n/a.

@@           Coverage Diff           @@
##           master     #188   +/-   ##
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  Coverage   67.76%   67.76%           
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  Files          15       15           
  Lines        2811     2811           
  Branches      439      439           
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  Hits         1905     1905           
  Misses        790      790           
  Partials      116      116