* A CA certificate (e.g. ca.crt) should be used to sign a server
certificate (server.crt for a private key server.key)
* gRPC API server requires a server certificate and key to be enabled
(passed via -cert-file and -key-file)
* gRPC client bootcmd tool must verify the server identity using a
known CA (passed to bootcmd via -ca-file)
* This provides transport security, it does not provide client
authentication
* Change assets download location to examples/assets
* FileStore should default to /var/lib/bootcfg/{profiles,groups,
ignition,cloud}
* Assets location should default to /var/lib/bootcfg/assets
* Fix -rpcAddress flag to be -rpc-address
* Split config.yaml files into JSON groups files
* Update examples to use folders of mountable groups files
* Stop reading groups from a -config config.yaml file
* Add RichGroup JSON <-> Protobuf Serialize Group
