Release 0.10

Preparing for hotfix release 0.9.1

Fix version

32bits platforms

Add grouped operations (quickwit-oss#493)

* [WIP] added UserOperation enum, added IndexWriter.run, and added MultiStamp

* removed MultiStamp in favor of std::ops::Range

* changed IndexWriter::run to return u64, Stamper::stamps to return a Range, added tests, and added docs

* changed delete_cursor skipping to use first operation's opstamp vice last. change index_writer test to use 1 thread

* added test for order batch of operations

* added a test comment

Refactoring

Bumping version

Release 0.7.1

Bump version pre-release