Organizationing (#102)

* Moving model-store into “generic” sub-directory.

Also adding a README.md to explain what belongs in “generic”

* Moving user-messages into “generic” sub-directory.

* Moving PageLoading into “generic” sub-directory.

* Moving “tabs” module into “generic” sub-directory.

* Moving InstructorToolbar and MasqueradeWidget up to instructor-toolbar.

The masquerade widget is a sub-module of instructor-toolbar.

* Co-locating celebration APIs with celebration utils.

Also adding an ADR about thunk/API naming conventions and making some other areas of the code adhere to it.

* Moving courseware data (thunks, api) into the courseware module.

Note that cousre-home/data/api still uses normalizeBlocks - this should be fixed so it’s not reaching across.  Maybe we pull that particular API up top.

This PR includes a few TODOs for things I saw, as well as a tiny bit of whitespace cleanup.

src/courseware/data/slice.js

@@ -0,0 +1,61 @@
+/* eslint-disable no-param-reassign */
+import { createSlice } from '@reduxjs/toolkit';
+
+export const LOADING = 'loading';
+export const LOADED = 'loaded';
+export const FAILED = 'failed';
+export const DENIED = 'denied';
+
+const slice = createSlice({
+  name: 'courseware',
+  initialState: {
+    courseStatus: 'loading',
+    courseId: null,
+    sequenceStatus: 'loading',
+    sequenceId: null,
+  },
+  reducers: {
+    fetchCourseRequest: (state, { payload }) => {
+      state.courseId = payload.courseId;
+      state.courseStatus = LOADING;
+    },
+    fetchCourseSuccess: (state, { payload }) => {
+      state.courseId = payload.courseId;
+      state.courseStatus = LOADED;
+    },
+    fetchCourseFailure: (state, { payload }) => {
+      state.courseId = payload.courseId;
+      state.courseStatus = FAILED;
+    },
+    fetchCourseDenied: (state, { payload }) => {
+      state.courseId = payload.courseId;
+      state.courseStatus = DENIED;
+    },
+    fetchSequenceRequest: (state, { payload }) => {
+      state.sequenceId = payload.sequenceId;
+      state.sequenceStatus = LOADING;
+    },
+    fetchSequenceSuccess: (state, { payload }) => {
+      state.sequenceId = payload.sequenceId;
+      state.sequenceStatus = LOADED;
+    },
+    fetchSequenceFailure: (state, { payload }) => {
+      state.sequenceId = payload.sequenceId;
+      state.sequenceStatus = FAILED;
+    },
+  },
+});
+
+export const {
+  fetchCourseRequest,
+  fetchCourseSuccess,
+  fetchCourseFailure,
+  fetchCourseDenied,
+  fetchSequenceRequest,
+  fetchSequenceSuccess,
+  fetchSequenceFailure,
+} = slice.actions;
+
+export const {
+  reducer,
+} = slice;