We'll use a JWT in the `Authorization` request header to identify the
user saving a page. The token will need to be set in the _authorization
token_ field in the SingleFile configuration so it will be included when
uploading.
The default messages printed when the process panics because the
configuration could not be loaded or the application context could not
be initialized are somewhat difficult to read. Instead of calling
`unwrap` in these cases, we need to explicitly handle the errors and
print more appropriate messages.
