feat(logger): Convert to using slog

[Pokom]

This introduces using slog as a structured logger for the project. Created a LevelHandler struct that is responsible for only logging out messages below a configured log level. Extended the config object to have a Log configuration to set

• Level
• Output
• Type

Added the following command flags:

• log.level (debug, info, warn, error)
• log.output (stdout, stderr)
• log.type (json, text)

Updated the csp and collector entrypoints to have accept a *slog.Logger parameter. Started updating existing log.Printf statements to use appropriate logging.

TODO:

• [ ] Update all collectors to accept a logger parameter

• [ ] Determine best way to pass logger to helper methods that current log out via log.Printf

• relates #32

[Pokom]

I'm going to close this PR in favor of breaking this up into smaller chunks. I'll keep the branch around temporarily as I use it for reference