veyron2/services/watch: Split up Watch interface by request type.

Specifics:
 - introduce GlobRequest and GlobWatcher, QueryRequest and QueryWatcher.
 - introduce the ResumeMarker type that aliases []byte, to have an explicit,
   consistent type across requests.
 - add raw.Request and the WatchRaw method to the raw store API.
 -- will add security labels in a separate commit related to store security.

Change-Id: I818769cee96f70b0d37aba2a85eb87295a51a041
16 files changed
tree: 29e6a26b2fb6acf651fd3e5ad0c7833be7142e11
  1. examples/
  2. lib/
  3. runtimes/
  4. security/
  5. services/
  6. tools/