Big Transaction refactor

[robbyphillips]

Previous transaction total routes still need to be fixed, but there's a lot of big changes here.

• Changes to models/Transaction.js

  • renamed userId field to fromUser
  • renamed paidUserId field to paidUser
  • added userId, commentId, postId, and isListokaAcct to txOutputs array
  • remove commentList

• Created scripts/transactionSeed.js and added it to the npm run seed command in package.json

  • Create 15 batch comment transactions for each user
  • Create 3 post purchase transactions for each user
  • Use random date generator to give transactions different createdAt times

• Added routes and handlers to routes/transactionRouter.js to get all transactions for a given userId.

  • /users/:userId/tx for both 'to' and 'from' transactions
  • /users/:userId/tx/to, /user/:userId/tx/from
  • All of these routes take query params for pagination, for example /users/:userId/tx?page=2&limit=10

• Added helpers to client/src/utils/API.js for the transaction routes

• Modified ListokaMoneyButton to work with the new Transaction model (pretty sure this is non-breaking for any of our current use-cases)

• Misc cleanup.