Implement a new error handling library based on pkg/errors. It provides
stack saving on wrapping and exports some function to add stack saving
also to external errors.
It also implements custom zerolog error formatting without adding too
much verbosity by just printing the chain error file:line without a full
stack trace of every error.
* Add a --detailed-errors options to print error with they full chain
* Wrap all error returns. Use errors.WithStack to wrap without adding a
new messsage and error.Wrap[f] to add a message.
* Add golangci-lint wrapcheck to check that external packages errors are
wrapped. This won't check that internal packages error are wrapped.
But we want also to ensure this case so we'll have to find something
else to check also these.
Replace zap with zerolog.
zerolog has a cleaner interface and can be easily configured with custom
error chain printing using a new error handling library that will be
implemented in another PR.
Just a raw replace of "github.com/pkg/errors".
Next steps will improve errors (like remote errors, api errors, not exist errors
etc...) to leverage its functionalities
* Rename to datamanager since it handles a complete "database" backed by an
objectstorage and etcd
* Don't write every single entry as a single file but group them in a single
file. In future improve this to split the data in multiple files of a max size.
Simone Gotti