Improve error message when we can't find hass config dir

[balloob]

In db_from_hass_config, when config.find_hass_config() raises a ValueError, we should print instructions on how a user should manually create a db instance from their DB url.

HASS-data-detective/detective/core.py

Line 17 in a2f0922

path = config.find_hass_config()