Support Consul Admin Partitions

[Esity]

Currently it would appear that when registering external services inside the default admin partition and in any namespace, Consul ESM works as expected.

However, when running Consul ESM against a specific admin partition with a token tied to a specific partition, it will not pick up the external nodes and services and they will sit forever.

I am also guessing because we are using go module consul 1.14.3, we are seeing some issues with this so this PR might be required for review/merging to fix this?
#253

This was setup using Hashicorp docs

[Esity]

Correction, PR was #253

[Esity]

Looks like there is a draft PR for this that has been tested @blake
#281