* Problem: we have unused and outdated fixtures
Solution: clean up fixtures and tests accordingly
* Problem: there are still unused fixtures
Solution: remove Merlin keys
* Problem: There are unnecessary markers
Solution: remove the tendermint marker for tests
* Problem: We need to store the `election_id` as part of the `validator_update` so we can efficiently check which election was resposible for the change
Solution: Added the parameter to `store_validator_set` and aligned the tests
* Problem: Logic for `upsert-validator show` is convoluted
Solution: Rewrote the function to be much simpler
* Problem: Need a uniqueness constraint for election_id wrt validator changes
Solution: Added a new key to the db schema
* Problem: Source files contain no license info
Solution: Add comments with SPDX license info to source files
* Python 3 files don't need # -*- coding: utf-8 -*-
* Problem: Validator set not tracked by BigchainDB
Solution: BigchainDB depends on tendermint's RPC API to get the validator set
which is not avaiable during replay so the validators set should be tracked
inside BigchainDB
* Problem: Unclear code and documentation
Solution: Fix decode_validator and docs strings
* Problem: Doc strings missing
Solution: Add doc string for store_validato_set
codegeschrei
Zachary Bowen
Troy McConaghy
Vanshdeep Singh