Change git clone command in getting started
Change git clone command in getting started

Changed git clone to git clone to git clone --depth=1 to reduce the cloning size as this is only for deployment of mycroft and not for development and  added additional instructions for developers to use the whole repo instead of single depth repo.
linuxipho/mycroft-core,forslund/mycroft-core,linuxipho/mycroft-core,forslund/mycroft-core,MycroftAI/mycroft-core,Dark5ide/mycroft-core,Dark5ide/mycroft-core,MycroftAI/mycroft-core