Release notes template

[carver]

What was wrong?

There was no title on the release notes page, so all the inner titles were spamming the docs homepage on https://eth-utils.readthedocs.io/en/stable/

How was it fixed?

• Add a title
• Clean up the eth-utils name in each sub-heading
• Add a few missed release notes from previous merges

To-Do

• [ ] Merge in project template to get the latest options for docs like *.performance.rst, *.docs.rst, etc

• [ ] Clean up commit history

• [ ] Add entry to the release notes

Cute Animal Picture

[carver]

This change got fully pulled into #207