e2e: Ensure Consul client is running before starting Nomad service.

[jrasell]

The recent change of the Consul fingerprinter means Consul must be up and started before the Nomad client, otherwise the Nomad process needs to be sent a SIGHUP.

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[tgross]

It looks like as of hashicorp/consul#16845 Consul supports systemd Type=notify and that's actually now part of their packaged unit file: https://github.com/hashicorp/consul/blob/main/.release/linux/package/usr/lib/systemd/system/consul.service#L9 We're not using that unit file (for reasons which were probably good at the time but may not make sense anymore). That should allow depends/wants to work correctly.

[tgross]

LGTM!

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