Allow content stores to ingest content without coordination of a daemon
to manage locks. Supports coordinated ingest and cross-process ingest
status.
Signed-off-by: Stephen J Day <stephen.day@docker.com>
Break up the content store prototype into a few logical files. We have a
file for the store, the writer and helpers.
Also, the writer has been modified to remove write and exec permissions
on blobs in the store.
Signed-off-by: Stephen J Day <stephen.day@docker.com>
