Description

• This PR add support for config file which will store all the Microcks configurations and contexts related information.
• It also adds support for context command, which will enable users to switch between multiple context and delete a context.
• As of now, there is no way to create a context. A context will be created once the user will perform a login operation.
• This PR also adds errors/error.go package which will help to check errors in our CLI tool and handle them appropriately.

** We have added support for config.yaml file with #143. With this PR we are going to add a new localconfig.go which will manage all the config related things. config.go file will be removed in upcoming PR.

** we have also changed the path for saving local config to $HOME/.config/microcks/config from $HOME/.microcks-cli/cofnig/.

Related issue(s)

Fixes #136