Optimize deploy upload

We send a tar file currently, add an initial step: transmit a manifest of files (path => sha256) and let the build look in the most recent OCI image of the last build to find the files. For each file it files, it stages it into the build directory. For the files it doesn't find, the build server sends back a list of files it couldn't find. Then deploy sends just a tar with those files and untars it into the build directory.