Migrate CI to GitHub runners. (#21)

Migrate some CI steps to GitHub runners. While two steps that requires k8s cluster still remains on self-hosted, because resource requested is exceed the standard configuration of GitHub runner (2 core CPU, 8G memory).

This PR also

* Parallels the building process of three engines,
* Reduce the size of artifacts,
* Add code coverage report for graphscope.

However, this PR also introduced several overhead, which is two additional Dockerfile for assemble artifact content into graphscope-runtime image, however, this is basically copied from the stage 2 of the normal Dockerfile. And the manipulation of upload and download artifact is more complicated than before (to preserve file permissions of artifact, one need to assemble all files into a tar ball)

.github/codecov.yml

@@ -0,0 +1,20 @@
+codecov:
+  require_ci_to_pass: yes
+
+coverage:
+  precision: 2
+  round: down
+  range: "60...80"
+
+parsers:
+  gcov:
+    branch_detection:
+      conditional: yes
+      loop: yes
+      method: no
+      macro: no
+
+comment:
+  layout: "reach,diff,flags,files,footer"
+  behavior: default
+  require_changes: no