New and faster installer implementation (#2595)

* Improve the way packages are installed

* Add support for parallelized operations

* Improve the Chooser class

* Make the new installer the default

* Add an Authenticator class to be able to download from protected urls

* Adapt code and tests to latest changes

* Update lock file and some dependencies

* Improve installations information and caching

* Make the final adjustments and tests for the new installer

* Use the preview version of Poetry for the CI

* Rename Executor.run() to Executor.run_pip()

* Gracefully handle errors when executing operations