In Nomad 0.9, we made volume driver handling the same for `""`, and
`"local"` volumes. Prior to Nomad 0.9 however these had slightly different
behaviour for relative paths and named volumes.

Prior to 0.9 the empty string would expand relative paths within the task
dir, and `"local"` volumes that are not absolute paths would be treated
as docker named volumes.

This commit reverts to the previous behaviour as follows:

| Nomad Version | Driver  |   Volume Spec    | Behaviour                 |
|-------------------------------------------------------------------------
| all           | ""      | testing:/testing | allocdir/testing          |
| 0.8.7         | "local" | testing:/testing | "testing" as named volume |
| 0.9.0         | "local" | testing:/testing | allocdir/testing          |
| 0.9.1         | "local" | testing:/testing | "testing" as named volume |

Fixes #5566 .

Fix a case where docker logging process may lock up nomad agent restart.

Looks like we have a case where docker logger is started even through logmon isn't. In such case, the fifo writer blocks indefinitely and because the open operation happens in the main goroutine, nomad agent blocks indefinitely.

This fixes the issue where the fifo open operation happens in goroutine instead of main goroutine.

We should follow up independently to ensure logmon <-> dockerlogger ordering and consider having task recovery happen in non-main goroutine with some sensible timeouts.

vault: fix renewal time

Renewal time was being calculated as 10s+Intn(lease-10s), so the renewal
time could be very rapid or within 1s of the deadline: [10s, lease)

This commit fixes the renewal time by calculating it as:

	(lease/2) +/- 10s

For a lease of 60s this means the renewal will occur in [20s, 40s).

client: simplify kill logic

api: fix migrate stanza initialization

docs: Add docs for nomad-alloc-restart

cli: add support for periodic force evaluation

Add `nomad alloc restart` and `nomad status -verbose`

resolves #3251

UI: Make tests faster

vault namespaces: inject VAULT_NAMESPACE alongside VAULT_TOKEN

Refactor scheduler package to enable preemption for batch/service jobs

cli: add `acl token list` command, documentation

docs: fix some incorrect acl policy docs (typos, copy-paste errors)

website: Update hashicorp-middleman container to v0.3.39

Fixes Migrate to be initialized like RescheduleStrategy.

Fixes #5477

Revert accidental merge of pr #5482

Revert "fingerprint Constraints and Affinities have Equals, as set"
This reverts commit 596f16fb.

Revert "client tests assert the independent handling of interface and speed"
This reverts commit 7857ac59.

Revert "structs missed applying a style change from the review"
This reverts commit 658916e3.

Revert "client, structs comments"
This reverts commit be2838d6.

Revert "client fingerprint updateNetworks preserves the network configuration"
This reverts commit fc309cb4.

Revert "client_test cleanup comments from review"
This reverts commit bc0bf4ef.

Revert "client Networks Equals is set equality"
This reverts commit f8d43234.

Revert "struct cleanup indentation in RequestedDevice Equals"
This reverts commit f4746411.

Revert "struct Equals checks for identity before value checking"
This reverts commit 0767a466.

Revert "fix client-test, avoid hardwired platform dependecy on lo0"
This reverts commit e89dbb2a.

Revert "refactor error in client fingerprint to include the offending data"
This reverts commit a7fed726.

Revert "add client updateNodeResources to merge but preserve manual config"
This reverts commit 84bd433c.

Revert "refactor struts.RequestedDevice to have its own Equals"
This reverts commit 68978252.

Revert "refactor structs.Resource.Networks to have its own Equals"
This reverts commit 49e2e6c7.

Revert "refactor structs.Resource.Devices to have its own Equals"
This reverts commit 4ede9226.

Revert "add COMPAT(0.10): Remove in 0.10 notes to impl for structs.Resources"
This reverts commit 49fbaace.

Revert "add structs.Resources Equals"
This reverts commit 8528a2a2.

Revert "test that fingerprint resources are updated, net not clobbered"
This reverts commit 8ee02ddd.

More terraform updates

terraform: modified default client instance type to a more reasonable t2.medium, left commented GPU instance type