Add support for membership event history

While ./main.py is complete and gives to Duniter everything needed to bootstrap a network with correct initial state, ./squid-*.py scripts only cover:

• block history
• transaction history
• certification history

Membership event history is not covered as stated in todo: https://git.duniter.org/tools/py-g1-migrator/-/blob/effe52251c544f285e7213b1a0487b102e51309f/lib/functions.py#L174-L179

The history of membership renewal and revocation is then not available in duniter-squid and will not appear in Cesium v2.