chore: add configs, docs and scripts to generate semantic releases

This is the first iteration towards automating the release process. This MR adds everything that's required for maintainers to generate a new semantic-release locally and have it pushed to this repository.

Invoking the make release command will trigger the generation of a new semantic-release, doing the following:

1. Generate and append a new entry to CHANGELOG.md;
2. Commit changelog update in the format chore(release): <version>;
3. Create a new git tag in the format v<version>-gitlab;
4. Push commit and tag to the remote master branch.

A make release-dry-run command is also available.

The next step is to make this process happen within a GitLab CI pipeline, using a manually triggered release job.