Conf tweaks

- Enable configuration of main template again
- Retrieve a configuration file from a route param
- Add a default conf file as a fallback
- Extract main route to an angular constant (might help with testing later on)

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__UPDATE__

We now can start the app through two params:

- `conf`
We will provide some basic configurations that can be triggered by a single word, like `conf=staging`
Takes precedence over `conf_file`.

- `conf_file`
Awaits a uri to a configuration file.