feat: created migration to add a schema_version column on the user_config table

feat: adapted the new settings loader to work with the db instead of
the json file

fix: fixed the schema migration file

fix: updated accounts to work with the db

fix: fetch only data with the new schema version

fix: change the account saving process so there's no more than one
account record

chore: removed unnecessary TODO comments

fix: replaced an error throwing with a Promise reject

fix: when looking for the latest config, don't limit it to the new ones

fix: fix function names on gql server

fix: remove duplicate import

fix: return an empty object when there's no schema_version 2 config yet

lib/new-admin/graphql/schema.js

@@ -258,8 +258,8 @@ const resolvers = {
       serverLogs.getServerLogs(from, until, limit, offset),
     transactions: (...[, { from, until, limit, offset }]) =>
       transactions.batch(from, until, limit, offset),
-    config: () => settingsLoader.getConfig(),
-    accounts: () => settingsLoader.getAccounts()
+    config: () => settingsLoader.loadLatestConfig(),
+    accounts: () => settingsLoader.loadAccounts()
   },
   Mutation: {
     machineAction: (...[, { deviceId, action, cassette1, cassette2 }]) => machineAction({ deviceId, action, cassette1, cassette2 }),