Introduce GitHub Actions CI Workflow (#19449)

* Migrate subset of CircleCI ci workflow to GitHub Actions

Runs test-go and test-go-remote-docker with a static splitting of test packages

* [skip actions] add comment to explain the purpose of test-generate-test-package-lists.sh and what to do if it fails

* change trigger to push

---------

Co-authored-by: Kuba Wieczorek <kuba.wieczorek@hashicorp.com>

command/server/hcp_link_config_test.go

@@ -1,6 +1,7 @@
 package server
 
 import (
+	"os"
 	"testing"
 
 	"github.com/go-test/deep"
@@ -9,6 +10,10 @@ import (
 )
 
 func TestHCPLinkConfig(t *testing.T) {
+	os.Unsetenv("HCP_CLIENT_ID")
+	os.Unsetenv("HCP_CLIENT_SECRET")
+	os.Unsetenv("HCP_RESOURCE_ID")
+
 	config, err := LoadConfigFile("./test-fixtures/hcp_link_config.hcl")
 	if err != nil {
 		t.Fatalf("err: %s", err)