Warning messaging

[G4Vi]

Working on Updated Versioning. I added deprecation warnings for the old namespace dylibso_observe. However, I'm not sure they are going the right place or actually making it to the observe-sdk user across the languages and adapters. We should decide on a consistently policy for this and apply it everywhere.

Currently, the rust sdk outputs with log::warn! and the basic example is setup to by default log with warnings.

The go-sdk outputs to the standard logger with log.Println.

The js-sdk outputs with console.warn.