Streamline local application development setup

[sodre]

Environment Information

• ZeroAE's GitHub App framework version: 0.0.1
• Python version: 3.x
• Operating System: MacOS

Description

To facilitate the initial setup fo a github Webhooks, we should automatically register for a SMEE.IO channel if the inferred URL is localhost or equivalent just like it is done in Probot

• [x] Create a python implementation of the smee client.
• [ ] Start a smee client if the WEBHOOK_PROXY environment is set.
• [ ] During registration, if we detect that the the system was run in local-mode, then start a smee client, and save the WEBHOOK_PROXY configuration parameter.

[sodre]

The event-source-library is probably overkill, and the license is not compatible with Apache-2.0.

For the Probot-case a synchronous smee client is more than sufficient.