Add ability to restart both sidecar and task when service check is failing

### Proposal
`check_restart` stanza provides an ability to restart a task when a service check is not passing, but it doesn't restart a sidecar. Sometimes a task can be restarted forever when an problem is actually in a sidecar. A boolean toggle `restart_sidecar`can be added to a `check_restart` stanza to provide an ability to restart both tasks.

### Use-cases
It can be useful when a task cannot connect to a service behind a sidecar

### Attempted Solutions
Now I have to stop a sidecar task manually when receive an alert to fix a problem which happens from time to time

No files or tests are named. Start by locating the check_restart stanza handling and the existing task and sidecar restart paths, then trace how a failing service check triggers a restart. Done means a restart_sidecar toggle can restart both the task and its sidecar while preserving existing behavior when the toggle is absent.

Written by the indexing model from the issue text.