Multiple small changes

Readme improvements

• fix title
• Add packaging status badge from Repology

blocks command

• Display powMin in a row in the blocks explorer

Transaction fixes

• Use sleep from async.
• Close #232 (closed): Retrieve uid’s identities with a sleep in between not to reach the BMA limitation

DuniterPy

• Update to DuniterPy v0.57.0

CI/CD

• Change only/except to rules from .gitlab-ci.yml since it will be removed from GitLab v13.0