Improve Error Messaging for Actions by Using ExecutionContext's FileTable as Single Source of Truth and by Passing FileID to All Children Tokens. (#564)

* Composite Action Run Steps

* Env Flow => Able to get env variables and overwrite current env variables => but it doesn't 'stick'

* clean up

* Clean up trace messages + add Trace debug in ActionManager

* Add debugging message

* Optimize runtime of code

* 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

* Fix env format

* Remove comment

* Remove TODO message for context

* Add verbose trace logs which are only viewable by devs

* Initial Start for FileTable stuff

* Progress towards passing FileTable or FileID or FileName

* Sort usings in Composite Action Handler

* Change 0 to location

* Update context variables in composite action yaml

* Add helpful error message for null steps

* Pass fileID to all children token of root action token

* Change confusing term context => templateContext, Eliminate _fileTable and only use ExecutionContext.FileTable + update this table when need be

* Remove unnessary FileID attribute from CompositeActionExecutionData

* Clean up file path for error message

* Remove todo

* Fix Workflow Step Env overiding Parent Env

* Remove env in composite action scope

* Clean up

* Revert back

* revert back

* add back envToken

* Remove unnecessary code

* Add file length check

* Clean up

* Figure out how to handle set-env edge cases

* formatting

* fix unit tests

* Fix windows unit test syntax error

* Fix period

* Sanity check for fileTable add + remove unn. code

* revert back

* Add back line break

* Fix null errors

* Address situation if FileTable is null + add sanity check for adding file to fileTable

* add line

* Revert

* Fix unit tests to instantiate a FileTable

* Fix logic for trimming manifestfile path

* Add null check

* Add filetable to testing file, remove ? since we know filetable should never be non null

src/Test/L0/Worker/ActionManagerL0.cs

@@ -3584,6 +3584,7 @@ runs:
             _ec.Setup(x => x.Variables).Returns(new Variables(_hc, variables));
             _ec.Setup(x => x.ExpressionValues).Returns(new DictionaryContextData());
             _ec.Setup(x => x.ExpressionFunctions).Returns(new List<IFunctionInfo>());
+            _ec.Setup(x => x.FileTable).Returns(new List<String>());
             _ec.Setup(x => x.Plan).Returns(new TaskOrchestrationPlanReference());
             _ec.Setup(x => x.Write(It.IsAny<string>(), It.IsAny<string>())).Callback((string tag, string message) => { _hc.GetTrace().Info($"[{tag}]{message}"); });
             _ec.Setup(x => x.AddIssue(It.IsAny<Issue>(), It.IsAny<string>())).Callback((Issue issue, string message) => { _hc.GetTrace().Info($"[{issue.Type}]{issue.Message ?? message}"); });