[observability] Replace zap with log/slog

[zalgonoise]

Is your feature request related to a problem? Please describe.

This is a placeholder issue to replace the current usage (and references) of uber-go/zap with standard library's log/slog package. This allows a standard logging API for any Go application, where different implementations of its slog.Handler interface focus on actually registering the log events in the appropriate backend or target output.

Note: Log levels in log/slog range from Debug to Error, so any Fatal-level log entries should be replaced with Error-level ones, followed by an os.Exit(1), if that is really the desired behavior

Describe the solution you'd like

• The generated internal/log package contains new logic to create a log/slog logger instead of a uber-go/zap one.
• The generated go.mod file no longer references uber-go/zap
• All logger and logging references are replaced with log/slog equivalents

Suggestion:

• use log/slog's Attr (slog.String, slog.Bool, etc) functions when passing attributes to log events. This keeps the key-value pairs in the attributes neatly organized, as well as leveraging the package's proposed strongly-typed attributes

Describe alternatives you've considered

N/A - the standard library inclusion means that it should be used as a common (structured) logging API for Go applications. This doesn't mean that consumers of slog are tied to it completely -- its slog.Handler interface allows custom handling of the log events, so that custom behavior is still possible by calling slog.New with a custom slog.Handler.

Search

• I did search for other open and closed issues before opening this.

Code of Conduct

• I agree to follow this project's Code of Conduct

Additional context

No response

[zalgonoise]

Closing this issue as #311 was also created just a few minutes before :D

[MarvinJWendt]

You could have also closed mine, this one is way more detailed 😄
The only difference to my proposal is that I proposed to remove internal/log completely, as slog does not need a wrapper.
We could initialize the slog handler / logger directly in the entry point, I guess (just a single line of code).