Implement start, stop and restart methods.

Once we had agreed on the restart logic, the simplest thing to do was to generate the all methods based on that logic.

TODO: Add stop-sleep-start methods.
Can we pass the `-v` option to `svcadm` for verbose output if we are running in verbose mode?  i.e. the command would become `svcadm -v <method> <service>`.  In verbose mode it typically sends one line to stdout giving the full FMRI and what it did with it, e.g.

```
# svcadm -v disable smtp
svc:/network/smtp:sendmail disabled.
# svcadm -v enable smtp
svc:/network/smtp:sendmail enabled.
```

Without `-v` it sends nothing to stdout.