Remove unused helper functions and interfaces

## Description
There is currently some unused functions and interfaces in the PoC. To make it easier to read/understand/maintain the code long-term we should go through and remove this code.

A few places that come to mind at the time of writing this issue:
- This whole file: https://github.com/everettraven/telescopia/blob/main/pkg/cache/dynamic_cache_interface.go
- https://github.com/everettraven/telescopia/blob/c76339b193e66f424af9731b866c050b12169339/pkg/cache/helpers.go#L136-L158
- https://github.com/everettraven/telescopia/blob/c76339b193e66f424af9731b866c050b12169339/pkg/cache/helpers.go#L52-L81

## Acceptance Criteria
- remove unused code