Composite Actions Support for Multiple Run Steps (#549)

* Composite Action Run Steps

* Clean up trace messages + add Trace debug in ActionManager

* Change String to string

* Add comma to Composite

* Change JobSteps to a List, Change Register Step function name

* Add TODO, remove unn. content

* Remove unnecessary code

* Fix unit tests

* Add verbose trace logs which are only viewable by devs

* Sort usings in Composite Action Handler

* Change 0 to location

* Update context variables in composite action yaml

* Add helpful error message for null steps

src/Runner.Worker/action_yaml.json

@@ -32,7 +32,8 @@
             "one-of": [
                 "container-runs",
                 "node12-runs",
-                "plugin-runs"
+                "plugin-runs",
+                "composite-runs"
             ]
         },
         "container-runs": {
@@ -83,6 +84,36 @@
                 }
             }
         },
+        "composite-runs": {
+            "mapping": {
+                "properties": {
+                    "using": "non-empty-string",
+                    "steps": "composite-steps"
+                }
+            }
+        },
+        "composite-steps": {
+            "context": [
+                "github",
+                "needs",
+                "strategy",
+                "matrix",
+                "secrets",
+                "steps",
+                "inputs",
+                "job",
+                "runner",
+                "env",
+                "always(0,0)",
+                "failure(0,0)",
+                "cancelled(0,0)",
+                "success(0,0)",
+                "hashFiles(1,255)"
+            ],
+            "sequence": {
+                "item-type": "any"
+            }
+        },
         "container-runs-context": {
             "context": [
                 "inputs"