Field-based node properties
This updates REAPI proto and code to match https://github.com/bazelbuild/remote-apis/pull/128
Depends on BuildGrid/buildbox/buildbox-common!269, BuildGrid/buildbox/buildbox-casd!176 (merged) and BuildGrid/buildbox/buildbox-fuse!36 (merged). The Docker testsuite image has to be updated with a new BuildBox version for incremental workspace tests to work again. Non-incremental builds still work even without a BuildBox update.
Edited by Jürg Billeter