Sending "unknown" as segment name to X-Ray results in incorrect data displayed in the X-Ray UI

[robyf]

As part of #59 a check has been added that sends "unknown" as segment name to X-Ray when the received span doesn't have a remote service name. This solves the issue that X-Ray segments must have a name but creates issues on the X-Ray side, for example:

in this case the "unknown" segment belongs to the security-gateway-aws service and not to the test-app and in the service map "unknown" services appear as dependencies:

[codefromthecrypt]

Thanks for all the help

closed via 07d46d2 for now and https://docs.google.com/document/d/1ZFg2SX2DUJFRE8MpodV9DL9uYgNHe-90PMQIb1DrY8k/edit#

we can revisit as experience gains or alternate approaches become possible. For example adjusters on the collector side and whatnot.