Move datadog example (Docker) out of `/source`

[phlax]

Currently the datadog extension has a docker demo in the /source directory

To say this is unexpected would be to put it mildly - and unless im mistaken this is not part of the source at all.

If this is a demo then it should be moved to /examples and have the relevant documentation/testing added

[phlax]

cc @dmehala @mattklein123

[github-actions[bot]]

This issue has been automatically marked as stale because it has not had activity in the last 30 days. It will be closed in the next 7 days unless it is tagged "help wanted" or "no stalebot" or other activity occurs. Thank you for your contributions.

[dmehala]

no stalebot

EDIT: Quick head up. I am working on it this week.

[phlax]

brilliant thanks so much @dmehala that is really appreciated - i can help with creating a sandbox