refactor: move xmodule folder to root

- Moving xmodule folder to root as we're dissolving sub-projects of common folder in edx-platform
    - More info: https://openedx.atlassian.net/browse/BOM-2579
- -e common/lib/xmodule has been removed from the requirements as xmodule has itself become the part of edx-platform and not being installed through requirements
- The test files common/lib/xmodule/test_files/ have been removed as they are not being used anymore

xmodule/js/fixtures/imageinput.html

@@ -0,0 +1,35 @@
+<!-- ${id}     = 12345 -->
+<!-- ${width}  = 300   -->
+<!-- ${height} = 400   -->
+
+<div class="imageinput capa_inputtype" id="inputtype_12345">
+    <input
+        type="hidden"
+        class="imageinput"
+        src=""
+        name="input_12345"
+        id="input_12345"
+        value=""
+    />
+
+    <div style="position:relative;">
+        <div
+            id="imageinput_12345"
+            style="width: 300px; height: 400px; position: relative; left: 0; top: 0; visibility: hidden;"
+        >
+            <!-- image will go here -->
+        </div>
+        <div id="answer_12345" data-width="100" data-height="100"></div>
+    </div>
+
+
+    <!-- status == 'unsubmitted' -->
+        <span
+            class="unanswered"
+            style="display: inline-block;"
+            id="status_12345"
+            aria-describedby="input_12345"
+        >
+            <span class="sr">Status: unanswered</span>
+        </span>
+</div>