feat: Add initial template framework

Adds copy of https://gitlab.com/gitlab-org/security-products/analyzers/common/-/tree/master/template as incremental steps to reducing common project scope.

Note that this is a straight copy of the directory with one minor change of setting CHANGELOG to start with v2 given our current MAJOR pinning limitations.

I'd prefer to make any additional changes to these files as a follow-up (if needed) to keep this focused purely on seeding the project.

Relates to gitlab-org/gitlab#211819 (closed)