Add support for injecting APM trace details for every run

[vigneshshanmugam]

• Having the ability to propagate the trace details of each run would allow users to match each suite in the Uptime and APM UI.
• Heartbeat side is covered here - Support trace based linking with APM uptime#302

[graphaelli]

Expanding on this description a bit, I'm hoping we could start with detecting whether the Elastic APM RUM agent has instrumented the target and include trace id(s) associated with a synthetic step in their run results, to allow insight into where time was spent serving the synthetic check.

[paulb-elastic]

@vigneshshanmugam is this the same as #265

[vigneshshanmugam]

@paulb-elastic Yes, we can close this one in favor of #265