[WIP] Consolidation

[sirnicolaz]

some notes of things I (@vrde) want to fix in the feature freeze phase

Add a "whenever possible" in front of all these items:

• uint should be uint256 (add linter)
• functions should be marked virtual to make them overridable by new proxy implementations #26
• contracts must have an interface and implement it (e.g. Voting doesn't implement IVoting) #27
• Base contracts should not expose public methods #28
• unify ACL control sometimes we use AccessControl, sometimes we use a custom modifier #29
• Update integration tests to use token amounts in Ether, not Wei #45
• use simpler interfaces (search for IERC20Upgradeable)
• review all FIXMEs, TODOs
• lib/utils.ts and lib/config.ts overlap, merge them