Add smoothing filter in BW estimator

1) Add smoothing filter
2) Add dump() to dump internal stats and local logs
3) Remove the redundant input in get() methods.

Test: manual test
Test: atest com.android.server.wifi
Bug: 177942435
Bug: 176814295

Change-Id: I7fc0248688f8b7ef9fccd65b803be97a20a71338
9 files changed