* Support Vault Namespaces explicitly in CA config
If there is a Namespace entry included in the Vault CA configuration,
set it as the Vault Namespace on the Vault client
Currently the only way to support Vault namespaces in the Consul CA
config is by doing one of the following:
1) Set the VAULT_NAMESPACE environment variable which will be picked up
by the Vault API client
2) Prefix all Vault paths with the namespace
Neither of these are super pleasant. The first requires direct access
and modification to the Consul runtime environment. It's possible and
expected, not super pleasant.
The second requires more indepth knowledge of Vault and how it uses
Namespaces and could be confusing for anyone without that context. It
also infers that it is not supported
* Add changelog
* Remove fmt.Fprint calls
* Make comment clearer
* Add next consul version to website docs
* Add new test for default configuration
* go mod tidy
* Add skip if vault not present
* Tweak changelog text
Connor