Softmap working example and CI

Tasks

• Create an example based on softmap.
• Fix the Onionbalance integration.
• Test the example.
• Add this example in the CI pipeline.
• Update the documentation, including:
  • That with Onionbalance v3 an additional backend service restart is needed? This is not needed anymore since 7fa96975.
  • Overview (how it works).
  • A note that the setup relies in shared backend services for every site in a project.
  • More examples, covering other softmap topologies, like the simpler example of using Onionbalance in a single server for distributing load between CPUs (./onionspray config examples/softexample.tconf && ./onionspray start softexample && ./onionspray ob-start -a).

Time estimation

• Complexity: very small (0.5 day)
• Uncertainty: low (x1.1)
• Reference (adapted)