start implementation of approval workflows. Add nav, page, empty table, and status filtering

src/interfaces/approval.workflow.ts

@@ -0,0 +1,17 @@
+import {Module} from ".";
+
+export interface ApprovalWorkflow {
+    id: string;
+    name: string;
+    module: Module;
+    status: ApprovalWorkflowStatus;
+    approvers: string;
+    step: string;
+}
+
+export type ApprovalWorkflowStatus = "approved" | "pending" | "rejected";
+export const ApprovalWorkflowStatusLabel: {[key in ApprovalWorkflowStatus]: string} = {
+    approved: "Approved",
+    pending: "Pending",
+    rejected: "Rejected",
+};