SIM-CI-Run tests in parallel

[AgustinRamiroDiaz]

Backend tests with pytest are ran sequentially, which is not a problem for unit tests in general

The thing is that e2e tests are very slow, and they are running sequentially.
Running e2e tests in parallel will

• improve times
• save resources
• test concurrency and multi-tenancy

The only downside I see is that when debugging and reading logs we might get confused, but that's something we can leverage by running the tests locally and improving logs