Projects: update contracts for audits

[chadoh]

This contains the updated contract for Projects, and all associated changes.

Changes required for mainnet launch

• updated event BountyAdded with new param registryId; update return values in event handler
• new event AssignmentRejected
• initialize no longer accepts defaultToken; in template, remove everything related to defaultToken
• when running start:dev, as in test.sh, deploy StandardBounties contract to local blockchain
• update loadIssueData; no longer returns token or dataHash
• update getSettings; returns bountiesRegistry instead of settings.bountyAllocator
• update reviewSubmission, now requires a sixth param, tokenAmounts
• implement submitWork, which has been removed from Projects.sol, by using StandardBounties' fulfillBounty and listening for events from StandardBounties
• removed getSubmissionLength, use StandardBounties getBounty instead
• removed getSubmission, use StandardBounties getBounty instead. Inside the struct returned by getBounty there is a fulfillments array which contains all submissions & submitter info
• when listening for events from StandardBounties, ignore all events for bountyIds that we don't care about
• update addBounties; input tokenBounties changed to tokenTypes

Required for mainnet, but needs integration with some other in-progress work once it's all on dev

• ensure switching bounty token functions correctly
• remove hard-coded StandardBounties address from PlanningKit.sol

Post launch improvements

• handle new event BountyRemoved
• handle new event AwaitingSubmissions
• update getRepo; use openIssueCount
• use updateBounty
• use removeBounties
• use addBountiesNoAssignment
• unassign user when application or submission rejected, so same user can apply to work again

[ottodevs]

Since this seems a huge PR I will wait for it to be "Ready for review" and hopefully cleaned a bit