Update linting page to add flake8 configuration (and make some minor improvements)

[stichbury]

NOTE: Kedro datasets are moving from kedro.extras.datasets to a separate kedro-datasets package in
kedro-plugins repository. Any changes to the dataset implementations
should be done by opening a pull request in that repository.

Description

Created in response to #2473 to add a small amount of information about configuration.

Also added a few minor tweaks to clarify the purpose of formatting/linting and the differences between them.

Development notes

Changed one file, linted, rebuilt and inspected.

I'd value input on whether there's more configuration information I could add here or if I've put the most useful information in (to mirror what we do for the starters). I notice that we have slightly different config for flake8 for the Kedro project itself...would it be useful to add any other commonly used settings?

Checklist

• Read the contributing guidelines
• Opened this PR as a 'Draft Pull Request' if it is work-in-progress
• Updated the documentation to reflect the code changes
• Added a description of this change in the RELEASE.md file
• Added tests to cover my changes

[astrojuanlu]

I think this is a neat improvement over what we have now, but left a few comments, mainly food for thought (not necessarily for this PR)

[jmholzer]

Thanks, this is great work. These docs will be in a much better state after this merge.