Refactor app running to support config file/env vars
This adds support for configuring the application through configuration files as well as environment variables.
Command line options have precedence over environment variables which have precedence over configuration options.
Configuration parameters be put into config.py as well as instance/config.py, which is is ignored by .gitignore.
Configuring through environment variables requires the prefix of "WTSTATUS_", e.g.
WTSTATUS_DEBUG=True ./main.py run leads to running a debugging enabled server.
Through these changes support for deploying the application in a production environment with e.g. uwsgi is also enabled.