See merge request !1

-help file updated
-some cleanup in ebulk script:
 - sanitize data-lake-url
 - rename variables

- download chunk size relies on remote file chunk size
- clearer log messages

- add to report method saves new large-hash parameter
- delete from report updated
- split download updated
- resume operation (both full and split files) updated
- warn conflicts updated
- update dataset operation updated
- rename operation (download and ingest)
- download discard changes updated
- stage feature works properly (add/remove local changes)
- ingestion reportUpToDate updated
- split ingestion updated
- dataset utils remove hardcoded url
- report up to date method updated

- see nexedi/ebulk#1

This reverts commit 469eb486.
http requests issue (see nexedi/ebulk#1) solved

- minor fixes in storage inputs
- retry on failed connections
- resume split operation for download
- control on first ingestion / partial ingestion
- report messages when storage ingestion finishes
- better control on exception and messages

- --discard-changes parameter on command pull
- new help and example files
- several fixes