Enable to specify author or namespace when mol init role *** runs

[xhiroga]

Summary

My idea is user can specify author or namespace by some variable, like command line option or environment variable.

For example

mol init role my_new_role --author xhiroga

# OR

export ANSIBLE_MOLECULE_AUTHOR=xhiroga
mol init role my_new_role

# There fill galaxy_info.author in meta/main.yml

Motivation

Because of that the author or namespace is not specified, running test for role will fail by default.

I expect that these option will help users who fail to run test without renaming author, like this issue.
#3267