* 1.8 changed the behavior of url.Parse so it is no longer
appropriate for parsing values like 0.0.0.0:8080
* Pass the address directly to http.ListenAndServe which gives
reasonable errors when bad values are given
* gRPC API server requires a CA certificate to verify
and authenticate clients (passed via -ca-file)
* gRPC clients must authenticate with a client certificate
and key (passed via -cert-file and -key-file)
* 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
* bootcfg/version package provides the linker's GIT SHA based
version to bootcfg components
* Display the bootcfg version via the HTTP server / path for
convenience and for validating a deployed version easily
* Log requests to the / rooted subtree paths to surface machines
which are making requests containing typos and mistakes that do
not match HTTP API endpoints
* 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
* Remove api.Store and use storagepb.Store instead
* Remove api.Spec and use storagepb.Profile instead
* Switch from api.Group to storagepb.Group
* Move api.Group to config for YAML config decoding only
* Allow bootcfg groups metadata to be defined via YAML
* Convert YAML metadata to JSON bytes field in a protobuf message
* Strip metadata except strings, string slices, and string-keyed maps
with nesting
* Use YAML group config to match machine labels to groups of zero or
more machines sharing a Specification
* Discontinue using machine.json resources representations which are
repetitive, don't support groups, and don't allow label matching
* Previous "default" special case now handled by a Group with an empty
matcher
