Add load tester for yamcs to simulate open mct traffic

[scottbell]

Closes #388

Describe your changes:

• Added a K6 script that subscribes to various Gyro YAMCS telemetry endpoints to simulate a heavy load on YAMCS.
• Added a K6 script that brings up a particular domain object (e.g., a display layout) with 30 browsers and dwells on the page for ~8m

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Author Checklist

• Changes address original issue?
• Tests included and/or updated with changes?
• Command line build passes?
• Has this been smoke tested?
• Testing instructions included in associated issue OR is this a dependency/testcase change?

Reviewer Checklist

• Changes appear to address issue?
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[scottbell]

Closing this PR as we're moving the scripts to https://github.com/unlikelyzero/openmct-performance