* 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.
* Consul service address is blank
Setting an explicit service address eliminates the ability for Consul
to dynamically decide what it should be based on its translate_wan_addrs
setting.
translate_wan_addrs configures Consul to return its lan address to nodes
in its same datacenter but return its wan address to nodes in foreign
datacenters.
* service_address parameter for Consul storage backend
This parameter allows users to override the use of what Vault knows to
be its HA redirect address.
This option is particularly commpelling because if set to a blank
string, Consul will leverage the node configuration where the service is
registered which includes the `translate_wan_addrs` option. This option
conditionally associates nodes' lan or wan address based on where
requests originate.
* Add TestConsul_ServiceAddress
Ensures that the service_address configuration parameter is setting the
serviceAddress field of ConsulBackend instances properly.
If the "service_address" parameter is not set, the ConsulBackend
serviceAddress field must instantiate as nil to indicate that it can be
ignored.
Previously the functional test was only testing the PCKS7-signed identity
document, not the detached RSA signature, so adding a test for that in the
functional test suite.
