Fixes#1574
BREAKING CHANGE: The `general` section in the config schema has changed: the `general.base_*`, `general.protocol` and `general.force_ssl` configuration fields have been replaced with a single `general.public_url` field. Be sure to use a valid url with the new configuration field.
- add django settings module documentation
- use default for previously required fields
BREAKING CHANGE: The API command line interface require the
configuration file to be present. The default configuration file path is
`/etc/airtime/airtime.conf`
* feat(legacy): allow custom port for database connection
- fix heredoc for php72
* update test config db section
* update sample config db section
* update api db config
* use defaults for database config section
* update documentation
* more documentation for migration