ci: add commitlint to enforce the Conventional Commits specification

[JoshuaLicense]

Description

Adds Commitlint to enforce conventional commits:

• A GitHub Action workflow which will be responsible for checking all PR titles.
• A Git Hook (via. Husky) which will be responsible for checking commit titles.

Related issue: https://dvsa.atlassian.net/browse/VOL-4966

Before submitting (or marking as "ready for review")

• Does the pull request title follow the conventional commit specification?
• Have you performed a self-review of the code
• Have you have added tests that prove the fix or feature is effective and working
• Did you make sure to update any documentation relating to this change?