Create module for adding a snapshot of an aurora cluster instance.

[choilmto]

Link related issues:

• Progress towards #48

Changes/added features:

• Add module for aurora snapshots

The following short checklist should be used to make sure your PR is of good quality, and can be merged easily:

• [x] follows project conventions
• [x] follows project principles
• [x] ./run.sh works correctly for all new examples
• [x] CI checks pass
• [x] mergeable to main (no conflicts)
• [x] Milestone linked (if applicable)

Reviewers: @ianmiell @ttarczynski @sanyer

[ttarczynski]

LGTM I'll merge it once the tests on integration are done. It can take a while because there's another big pull request being tested now.