[Enhancement] Switch to stdlib logger for logs

[syeopite]

Kemal's (and in turn Invidious') logger originated from a time where the Crystal standard library did not possess a logging library.

But it does now and it's much better than what Invidious currently uses in both performance and flexibility.

For example the stdlib version won't perform the string interpolation for the message when the severity level doesn't allow it unlike Invidious's current logger.

And it also provides the APIs necessary to emit logs to multiple different sources at once, and to toggle and change the severity level for different sections of the code as needed.

Though for a first implementation a simple search and replace on Invidious's log calls to the stdlib block syntax plus the necessary boiler plate should be enough imo.