Support abstract structured logger interface

[zchee]

Currently, the logger depends go.uber.org/zap package.

Should provide the abstract (but structured) Logger interface for developers who use the protocol package.

Like go-logr/logr, but Language Server Protocol specific.

[stefanvanburen]

Should this package just target slog as the logger?

[zchee]

@stefanvanburen
Yes, When I create this issue, not exist slog. But slog has been one of Go community de-fact logger.
I planned switch to using slog instead of go-logr.

Current status of this repository, See also:
#48 (comment)