module/apmgrpc: set span destination context

[axw]

Update the apmgrpc client interceptor to record
span destination address/port and context for
service maps.

Closes #767

[apmmachine]

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• Build Cause: Pull request #861 updated

• Start Time: 2020-12-16T06:31:21.581+0000

• Duration: 23 min 24 sec

Test stats 🧪

Test	Results
Failed	0
Passed	7662
Skipped	188
Total	7850