Allow for processing individual adaptor repos

Example usage:

    # will import all known adaptor modules, same as before
    import_repo_docs

    # will only import docs from hybridgroup/artoo-gpio
    import_repo_docs hybridgroup/artoo-gpio

    # will only import docs from hybridgroup/artoo-gpio
    import_repo_docs https://github.com/hybridgroup/artoo-gpio.git