[locationd] Add input checks

[nuwandavek]

There are currently a lot of checks before observations are input into the kalman filter. This can lead to silent degradation of the filter if observations from some sensors are not used for a while (this is currently not tracked). Also, there are checks inside the filter (EKF) implementation to ignore observations older than some time buffer. We want to make sure we have visibility into all observations that are ignored, and act accordingly.

There are two types of checks

• Value based checks: Failures here are acceptable if under some frequency
• Time based checks: Failures here are not acceptable

Todo:

• [x] Test on ~100k segments and compare to master
• [x] Test on synthetic segments with errors
• [x] Test on actual segments with error
• [x] Make sure process replay segments are actually testing locationd