Add passing checks count to configauditreport summary

[mlevesquedion]

Fixes #334.

Here is the output I get for the nginx deployment from the getting started docs:

$ kubectl create deployment nginx --image nginx:1.16
$ starboard scan vulnerabilityreports deployment/nginx
$ kubectl get configauditreports.aquasecurity.github.io -o wide
NAME               SCANNER   AGE   PASS   DANGER   WARNING
deployment-nginx   Polaris   1s    9      0        8

[codecov]

Codecov Report

Merging #348 (a2205d0) into main (725dd4f) will increase coverage by 0.02%.
The diff coverage is 100.00%.

@@            Coverage Diff             @@
##             main     #348      +/-   ##
==========================================
+ Coverage   66.16%   66.18%   +0.02%     
==========================================
  Files          57       57              
  Lines        2843     2845       +2     
==========================================
+ Hits         1881     1883       +2     
  Misses        721      721              
  Partials      241      241              

Impacted Files	Coverage Δ
pkg/polaris/plugin.go	90.08% <100.00%> (+0.16%)	⬆️

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[danielpacak]

LGTM Thank you @mlevesquedion and sorry for the trouble with conflicting changes in Polars tests.