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/

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Migrated from D488 (view on Phabricator)

Merge request was accepted

approved this merge request

fix https://https://

rebased

Some references in the commit message have been migrated:

• T1242 is now swh-environment#1242 (closed)

fix typo in commit msg

Merge request was merged

closed