Pull logic out of nomad/Job.Register into admission controllers

[shoenig]

The Job.Register function makes use of fancy new new admission controller tooling for validating only a couple of recent things. Let's extract more blocks of logic out of this function into their own controllers, e.g.

• Volume Permissions
• Enforce Modify Index
• Valid Update Transitions
• Vault Policy Permissions
• Consul Connect Task Permissions
• Sentinel Policy Enforcement

This will help make these critical bits of functionality more easily individually testable.

[stale]

Hey there

Since this issue hasn't had any activity in a while - we're going to automatically close it in 30 days. If you're still seeing this issue with the latest version of Nomad, please respond here and we'll keep this open and take another look at this.

Thanks!

[stale]

This issue will be auto-closed because there hasn't been any activity for a few months. Feel free to open a new one if you still experience this problem 👍