needservice execution based on tags or other rules

[danwos]

needservices request data from external services, which may be available and therefore the build crashes or stops.

There shall be an option, that indicates if needservice shall be executed or not.

This es helpful, e.g. for local development or readthedocs, where a company internal service may not be available.

tech. spec

#conf.py
needs_services = {
    'github-issues':     
        'url': 'https://api.github.com/',
        'alternative': some_rst_in_a_var,
        'alternative_trigger: 'python_statement' # like filter string
        ''
    }
}