VACMS-19450: Creates Banner Module

[dsasser]

Summary

Adds a new Banner module to the codebase. This will house the new banner api we are building.

Related issue(s)

https://github.com/department-of-veterans-affairs/va.gov-cms/issues/19450

Testing done

Automated using RSPEC tests.

Screenshots

What areas of the site does it impact?

Banners

Acceptance criteria

• [x] I fixed|updated|added unit tests and integration tests for each feature (if applicable).
• [x] No error nor warning in the console.
• [x] Events are being sent to the appropriate logging solution
• [x] Documentation has been updated (link to documentation)
• [x] No sensitive information (i.e. PII/credentials/internal URLs/etc.) is captured in logging, hardcoded, or specs