Add aggregate_cdf to visualize CDF/CCDF of multiple archives

[btjanaka]

Description

Resolves #126

TODO

• Add to ribs/visualize/__init__.py
• Implement in ribs/visualize/_aggregate_histogram.py
• Add tests in tests/visualize/aggregate_histogram_test.py
• Add and check documentation

Questions

1. Naming -- aggregate_cdf or aggregate_histogram? At first, I named this aggregate_histogram, as strictly speaking, the function is quite generic and can plot a histogram. However, given that archive histograms are uncommon in the literature (I have personally never seen one), I think we should emphasize the CDF/CCDF use case. Furthermore, histograms are already somewhat covered in the archive_histogram function. Therefore, I decided to name the function aggregate_cdf and set cumulative=True as the default. Users can pass cumulative=-1 to get a CCDF, and cumulative=False to get a histogram. Support for this will be included in the documentation, but it will not be emphasized as a use case.

Status

• I have read the guidelines in
  CONTRIBUTING.md
• I have linted and formatted my code with ruff and pylint
• I have tested my code by running pytest
• I have added a description of my change to the changelog in HISTORY.md
• This PR is ready to go