Update release templates
Follows chat conversation.
- Try to make it clearer when it's the main release, a patch release, or a security release.
- Update frontmatter
- Specify which products (CE, EE) are affected by each version. E.g.; "8.15.7 (CE, EE)" or "8.16.3 (CE)"
- Make the title short; the info about the main features should be in the description, not in the title. The are both displayed on the post's hero.
- Remove "GitLab" as the author: we dropped this long ago, preferring to attribute the post to a real person. Using "GitLab" as the author should be an option only for extremely delicate situations (e.g. DB outage post).
- Security Release template content should be completed by security team members (they know what should be included better than I do ;)
cc/ @ernstvn @briann @ClemMakesApps @JobV @dblessing @DouweM @rspeicher @stanhu