Create new fabrics8-services repository for common (shared) code

[stooke]

A new repo is proposed that contains code common to several of the current fabrics8-services repos.

Included in this new repo should be common error handling and logging code, along with whatever else is suggested. A readme file should document common coding idioms in the fabrics8-services organization.

This will aid consistency between the various services and help onboarding newcomers to the project.
Also, it makes it easier to avoid circular dependencies - for example, the Tenant service currently relies on WIT for logging code.

There should be no need for any service to reference anything other than the client code of another repo.
(Currently this is handled by referencing the design package and rebuilding using Goagen in the calling repo - this issue does not attempt to change that)

After creation, the various fabrics8-services can be refactored to use this repo.

In the comments, please add suggestions for the mane and contents of this repo.

[joshuawilson]

@aslakknutsen WDYT?

[stooke]

I've just found that in WIT, both Auth and WIT have code that initializes the global logging...

[stooke]

A common code repo seems like a good place for global utilities, like space name verification, etc.

[joshuawilson]

@aslakknutsen and @xcoulon were talking about this today.

[stooke]

@xcoulon has create repos fabric8-services/fabric8-common and fabric8-services/fabric8-starter to address this. Common code (and a sample main.go) will go in common, while a small starter service will go in starter.

Issues will be created to capture the discussion around the initial contents of those repos.