Add gh action for ci test and coverage

Test Krill isolated for now.

Change-Id: I7aa029e2be44b039411b975d7b90291f9ded89e5
diff --git a/.gitignore b/.gitignore
index a236671..5a11e10 100644
--- a/.gitignore
+++ b/.gitignore
@@ -17,6 +17,7 @@
 /misc/web-api.md
 *~
 .*
+!.github
 !.gitignore
 # /src/main/resources/
 /src/main/resources/server.properties