Migrate to the `just` build system and add release tooling

[carreter]

Changes in this PR

• Create justfile with documentation on how to use it
• Add GitHub action to automatically make a release on tag push

Why are you making these changes?

Having a unified build system will make it easier for devs to replicate what happens in our CI/CD systems locally. Also automation is good (generally)!

Are any changes breaking? (IMPORTANT)

No, these are purely devops changes

Pre-merge checklist

All of these must be satisfied before this PR is considered ready for merging. Mergeable PRs will be prioritized for review.

• [x] New packages/exported functions have docstrings.
• [x] New/changed functionality is thoroughly tested.
• [x] New/changed functionality has a function giving an example of its usage in the associated test file. See primers/primers_test.go for what this might look like.
• [x] Changes are documented in CHANGELOG.md in the [Unreleased] section.
• [x] All code is properly formatted and linted.
• [x] The PR template is filled out.

[ethanholz]

@carreter per your request in the Discord I took a look at this and it looks great! Looks like your tests ran correctly too which is the big win!