Refactor helper scripts to use kredits module

This reuses the kredits library functions in the helper scripts and
seeds. We no longer need to add IPFS hashes manually but simply can
provider contributor/proposal data.

package.json

@@ -8,7 +8,7 @@
   },
   "scripts": {
     "build-json": "truffle compile && node ./scripts/build-json.js",
-    "bootstrap": "truffle migrate --reset && truffle exec scripts/seeds.js && npm run build-json",
+    "bootstrap": "truffle migrate --reset && npm run build-json && truffle exec scripts/seeds.js",
     "ganache": "ganache-cli -p 7545 -i 100 --db=./.ganache-db -m kredits",
     "dev": "truffle migrate && npm run build-json",
     "test": "echo \"Error: no test specified\" && exit 1"
@@ -24,6 +24,7 @@
   },
   "homepage": "https://github.com/67P/truffle-kredits#readme",
   "devDependencies": {
+    "async-each-series": "^1.1.0",
     "ganache-cli": "^6.0.3",
     "promptly": "^3.0.3",
     "truffle": "^4.1.3",