Wrap `cic_eth` celery api in HTTP

Problem

To use a custodial web wallet, the celery API must be interfaced with a HTTP API.

Solution

• Define an OpenAPI spec describing one-to-one mappings to all api calls in cic_eth/api/api_task.py for HTTP
• Add the HTTP implementation to cic-eth-server

Progress

• OpenAPI Spec
• Authentication
• Cache
• Wei conversions

Routes

• /tokens
  • wrapped
  • tested
• /token
  • wrapped
  • tested
• /default_token
  • wrapped
  • tested
• /balance
  • wrapped
  • tested
• /transactions
  • wrapped
  • tested
• /create_account
  • wrapped
  • tested
• /transfer
  • wrapped
  • tested
• /transfer_from
  • wrapped
  • tested