* Increase the timeout for indexing spaces
* Allow for making queries that are not constrained to a RootID
* Use nano precision for the Mtime
* Add a SpaceDebouncer
The debouncer can be used to delay operations on spaces until things
have settled down to avoid doing the same operation multiple times.
* Do not index subtrees until they have changed (i.e. the mtime differs)
* Also pass a user to the space debouncer func
* Trigger a rescan of the according space when an event is received
* Improve wording/logging
* Add changelog
* Get rid of superfluous GetUserByClaim call
* Fix tests
* Fix reindexing triggered by shares by using the event's SpaceOwner
* Bump reva to pull in the space owner events changes
* Fix changelog
* Fix linter issues
* Fall back to the executant if no owner was received from the event
* Bump reva and go-cs3apis
* Fix go.sum
* Bump core
* Adapt expected failures
* Tweak debounce settings
This avoids using a public global variable. It allows us to initialize
the default client a bit later (outside of init()). That way we can e.g.
properly initialize the in-memory registry.
The help flag is configured automatically by default already. We don't
need to redo that for every single service.
This also addresses one of the finding of "go race" (#4088)
