feat: preauthorization (#4339)

* feat: swagger 2.0 preauthorization methods
* tests: add cases for oas3 preauthorization
* docs: add new preauth docs; touch up existing auth docs
* tests: add `rootInject` tests
* docs: remove unfinished sentence

test/core/system/system.js

@@ -701,6 +701,36 @@ describe("bound system", function(){
     })
   })
 
+  describe("rootInjects", function() {
+    it("should attach a rootInject function as an instance method", function() {
+      // This is the same thing as the `afterLoad` tests, but is here for posterity
+      
+      // Given
+      const system = new System({
+        plugins: [
+          {
+            afterLoad(system) {
+              this.rootInjects.wow = system.dogeSelectors.wow
+            },
+            statePlugins: {
+              doge: {
+                selectors: {
+                  wow: () => (system) => {
+                    return "so selective"
+                  }
+                }
+              }
+            }
+          }
+        ]
+      })
+
+      // When
+      var res = system.getSystem().wow()
+      expect(res).toEqual("so selective")
+    })
+  })
+
   describe("error catching", function() {
     it("should encapsulate thrown errors in an afterLoad method", function() {
       // Given