Eremetic framework fix

[gisjedi]

#1684: Resolves issue of framework id being specified with a '/' in the name. Prohibits specifying / in the framework-name config.json field.

[surdy]

LGTM

[surdy]

Thanks @gisjedi

@ryadav88 I did not realize that it was not default package but the users input that lead to bad framework ID. At any rate good to have this validation. Do we have external facing documentation on guiding package contributors ? If yes then it would be a good to document this there.

[ryadav88]

@surdy we have a general tutorial but not for best practices. https://github.com/mesosphere/universe/blob/version-3.x/docs/tutorial/GetStarted.md