Reference: https://github.com/Azure/azure-cli/issues/6402 https://github.com/Azure/azure-cli/issues/6257 Ideas: 1. Allow `--content-type` accept multiple file extension to content type pairs. 2. Allow `--content-type-map` accept a configure file. 3. Allow a configuration file under `.azure` folder. 4. Allow a configuration file under the source folder.