The user configuration directory can be overridden via environment
variables or configuration files.
In the current implementation `Msf::Config.config_directory` should be
utilized for consistent location reporting. `Msf::Config.get_config_root`
is reserved to generation of a default location and should be considered
`private` as it ignores some injected configuration options. Currently
autoloading does not allow application of the `private` keyword to this method,
requiring guidance during development that module writers should access the
full configured `user` value of `Msf::Config.config_directory`.
not strictly required, these conversions keep us
up to date with latest rspec conventions and best practices
which will prevent use from having to convert them when they become
deprecated later
MSP-11153
Test the following paths in order and only return them if the path
exists:
1. MSF_DATABASE_CONFIG environment variable
2. ~/.msf4/database.yml
3. <project>/config/database.yml
Jeffrey Martin