Update k8s to enable HTTP ingress to the service

[vcarl]

This lets us run a regular-ol website, for instance, and use Discord interaction webhooks. Interaction webhooks will unblock #59 and resolve #84

[what-the-diff]

PR Summary

• Simplified Automation Pipeline: The system previously used Docker cache setup, which was part of GitHub Actions. This has been removed to streamline our workflow.
• Improved Cache Strategy For Faster Docker Builds: There's been a change in how we save data during Docker image creation. Rather than storing previous versions on GitHub, we're now using a Docker registry. This means faster image builds and, consequently, quicker deployment.
• Established Secure Connection Mechanism: We've added a 'ClusterIssuer' file, which is essentially a ticket to acquire secure certificates from a free, widely trusted provider, Let's Encrypt. This gives us the valid certificates required to improve our service's security.
• Enhanced Website Security with SSL Redirection: Furthermore, in cluster/ingress.yaml, changes have been made to introduce SSL redirection. This upgrade automatically switches users from an insecure HTTP connection to a secure HTTPS one, increasing overall website security. Also, the secret key name was switched to letsencrypt-prod-key for stronger security consistency and structure.

[vcarl]

Hmm

ERROR: failed to configure registry cache importer: pull access denied, repository does not exist or may require authorization: server message: insufficient_scope: authorization failed

[vcarl]

Removed some build cache changes and swapped it to just not cache at all. That's significantly faster, previously:

and now: