[Stdlib] VoteLib: tools for voting

[0o-de-lally]

A developer can leverage a shared infrastructure for voting.

Participation voting is the first to be implemented. See prior art in Polkadot "adaptive quorum biasing".

• [x] Participation vote
• [x] Vote ballot can be stored in third party contract.
• [x] Vote receipt is saved on the user account.
• [x] Test a contract importing and implementing.
• [x] Transactional tests
  • [x] Init vote
  • [x] Vote
  • [x] Close
  • [x] Retract

[0o-de-lally]

Because of deep refactor to VoteLib the commits are included here: https://github.com/0LNetworkCommunity/libra/pull/1249