Issue 4344 - DRAFT NOT FOR MERGE Experimental aggregation support

[m09526]

This is the draft implementation for review of adding simple ageoff filtering and very simple min, max, count, sum aggregation.

I've opened this for review of the current work before more work is done.

Make sure you have checked all steps below.

Issue

• [X] My PR addresses the following issues and references them in the PR title. For example, "Issue 1234 - My Sleeper PR"
  • Resolves https://github.com/gchq/sleeper/issues/4344

Tests

• [] My PR adds the following tests OR does not need testing for this extremely good reason:
  • TODO

Documentation

• [X] In case of new functionality, my PR adds documentation that describes how to use it, or I have linked to a separate issue for that below.
• [X] If I have added or removed any dependencies from the project, I have updated the NOTICES file.