Major rework: removing all database dependencies

[sonroyaalmerol]

Context

• Related to Replace Redis with SQLite #184

Choices

• Removing any database dependency (Redis/SQLite) will remove any overheads unrelated to the load balancing of the proxy itself.
• This will make service leaner and more stable (due to having less/no dependencies).

Test instructions

Checklist before requesting a review

• I have performed a self-review of my code
• I've added documentation about this change to the README.
• I've not introduced breaking changes.

[github-actions]

The Docker image for this pull request has been built and pushed to GHCR.

Image URL: ghcr.io/sonroyaalmerol/m3u-stream-merger-proxy:pr-187