This reverts commit 65ba952f.

* Add custom certificate authority and client certificate support

* Add documentation on certificates

* Add cli options to publish for cert and custom ca

* Fix requests+pathlib problem and logic hole when BasicAuth+certs are used

* Rename custom-ca to cert

* Make black happy

Fixes #1153

Currently Poetry will detect that it is running in a usual virtual env
created with "python -m venv" and will not create an additional env.

This commit extends this logic to Conda, which uses different
environment variables to indicate running in a virtual env.

Conda's "base" env is treated specially to avoid polluting global
namespace.

* Refactor the environment management code

* Improve executable selection when current Python is incompatible

* Allow uploading of wheels with local version identifier

Signed-off-by: Oleg Höfling <oleg.hoefling@gmail.com>

* extracted pep-427-style name/version escaping to helper functions

Signed-off-by: Oleg Höfling <oleg.hoefling@gmail.com>

-- `package` from provider.py:search_for_directory
   is missing root_dir value. This fixes the problem.
-- fix https://github.com/sdispater/poetry/issues/1455

* Fix PATH being altered after installation even though choose not to

* Remove unuse updated list variable