Big overhaul replacing selenium by puppeteer. This does not work for now due to
problems with SSL being a requirement for external endpoints.

Add docker-compose.yaml file

- Add ports, volumes, env_file and environment options
- Update the .gitignore to add .env file
- Access URL for the external services now uses docker-compose hostnames.
- selenium-server is now a container service dependency

Selenium is no longer directly managed by directly by hublot, but is instead an
external service dependency.
This dependency is managed in docker-compose with a selenium server image.

This simplifies a LOT of things and make the project organization cleaner.

hublot now uses fake media sources for its audio and video.

Add base64-encoded avatar of hublot

Extract keywords and propose recommendation links based on transcription segments which are sent by the participants

Allow chromium to access insecure content. This is required for now as not all
external services expose secured endpoints.

This should not cause a problem in practice, but is still bad. We should ensure
that this will not be needed in the future.

See issue #22.

Add client lib to archive transcripts of meetings.

Add `client/external.js` which load third-party scripts passed into the
`externalLibs` array of the client config object.

Extract conference participants audio streems, and sending them to Kaldi server to transcription using websockets

Client config is now defined in `config.json` and injected by the runner into
the client side.
This allows to pass a single unified config object to each client-side script.

Refactor previous system into this.

Fixes #10