Move autoreducer to 3.1 in docker containers and add systemtest for new HIMEM autoreducer queue

[rosswhitfield]

EWM4385

This adds a new docker container to the docker-compose that only processes HIMEM jobs.

A system test is written to have a task that send the reduction to the different queue and check that the correct container actually runs the task.

This also bumps the postprocessing version used to v3.1.0

This PR doesn't actually change any code for webmon itself, just test that it works correctly with the new postprocessing stuff

Short description of the changes:

Long description of the changes:

Check list for the pull request

• I have read the [CONTRIBUTING]
• I have read the [CODE_OF_CONDUCT]
• I have added tests for my changes
• I have updated the documentation accordingly

Check list for the reviewer

• I have read the [CONTRIBUTING]
• I have verified the proposed changes
• best software practices
  • all internal functions have an underbar, as is python standard
  • clearly named variables (better to be verbose in variable names)
  • code comments explaining the intent of code blocks
• All the tests are passing
• The documentation is up to date
• code comments added when explaining intent

Manual test for the reviewer

References

[backmari]

Looks good! Thanks for adding the system test.