Display task lifecycle info in `nomad alloc status <alloc_id>` output.
I chose to embed it in the Task header and only add it for tasks with
lifecycle info.

Also, I chose to order the tasks in the following order:

1. prestart non-sidecar tasks
2. prestart sidecar tasks
3. main tasks

The tasks are sorted lexicographically within each tier.

Sample output:

```
$ nomad alloc status 6ec0eb52
ID                  = 6ec0eb52-e6c8-665c-169c-113d6081309b
Eval ID             = fb0caa98
Name                = lifecycle.cache[0]
[...]

Task "init" (prestart) is "dead"
Task Resources
CPU        Memory       Disk     Addresses
0/500 MHz  0 B/256 MiB  300 MiB
[...]

Task "some-sidecar" (prestart sidecar) is "running"
Task Resources
CPU        Memory          Disk     Addresses
0/500 MHz  68 KiB/256 MiB  300 MiB
[...]

Task "redis" is "running"
Task Resources
CPU         Memory           Disk     Addresses
10/500 MHz  984 KiB/256 MiB  300 MiB
[...]
```