setup: prepare pypi upload
- revamp setup.py
- add a (minimalistic) README file
- add build/ and dist/ to gitignore
related to swh-environment#1242 (closed)
Test Plan
https://test.pypi.org/project/swh-vault/
Migrated from D488 (view on Phabricator)
Staging instance, all changes can be removed at any time
related to swh-environment#1242 (closed)
https://test.pypi.org/project/swh-vault/
Migrated from D488 (view on Phabricator)