resource descriptions in multiple files

paths mirror the URI "templates", including colons in names of
"variables", and GNU make simply does not work with such paths.
bye GNUmakefile, hello Rakefile.
overlay files: resources fleshed out
GPG keys: resources fleshed out
appliance status, config have their own URIs

per feedback from Cornelius, David.
build requests are issued with POST /builds/queued

per feedback.
appliance repositories payloads fleshed out
resources for repositories fleshed out

feedback from Cornelius and David wants repository URLs
to contain their synthetic ids, not names.  i'll get to that.
resources for selected software fleshed out