XRay Remote Sampler accumulates Quota balance above assigned quota

[jj22ee]

The XRay sampling rules are of format x requests per second, and a rate of y.
However, the implementation of the sampler in golang allows the x requests to accumulate over time if not used. This is not desirable as it can allow for an unexpected increase burst of sampled requests after long time periods between requests.

Issue Details:

• When quota is run out, quotaBalance is refreshed.
• When quotaBalance is refreshed, it is increased by: (seconds since last refresh) * quota
  • If quotaBalance is refreshed 5 seconds after previous refresh, then quotaBalance gains 5*quota. There should NOT be 5*quota available to be used.

Quota balance should be capped to 1*quota