Number of connections to the monitored container, netstat

## Feature Request

Opening a feature request kicks off a discussion.

### Proposal:
Ability to monitor the number of connections in the container
### Current behavior:

### Desired behavior:
Netstat just like monitoring linux host
### Use case:

No files, tests, or entry points are named. Start by locating the existing Linux host netstat monitoring and the collectors that run against containers, then determine how a container connection count should be exposed; done means the metric is collected for monitored containers and covered by an appropriate test.

Written by the indexing model from the issue text.