* Create a new command/config subpackage.
This PR extracts the functions associated with loading and parsing
configs, and the DefaultTokenHelper, into a command/config subpackage,
just like TokenHelpers are in the command/token subpackage. The goal is
to allow other clients (in this case, the Vault and Nomad Terraform
providers, but in theory any client that wants to lean on Vault's
default behaviour) to reuse this logic and not drift from Vault, without
vendoring the entirety of Vault.
To retain backwards compatibility, I didn't remove any functions from
the command package; I just copied them into the command/config package,
and update the functions in the command package to call through to the
config package.
This was a flawed test. Previously the test passed in a fixture that
corresponded to a CLI config file, not an actual policy. The test
_should_ have been failing, but it wasn't. This commit adds a new
fixture.
Functionality is split into ExternalTokenHelper, which is used if a path
is given in a configuration file, and InternalTokenHelper which is used
otherwise. The internal helper no longer shells out to the same Vault
binary, instead performing the same actions with internal code. This
avoids problems using dev mode when there are spaces in paths or when
the binary is built in a container without a shell.
Fixes#850 among others
