Reorganize directory structure (#825)

* Remove docs folder.

This was a redirect from a GitHub pages site that does not appear
to be in use.

* Rename api folder to api-samples.

* Move examples to functional-samples folder.

* Move cookbook sample to functional-samples.

* Move tutorials to functional-samples folder.

* Move mv2 and apps folders to _archive.

* Rename tools folder to .repo.

* Move reference folder to functional-samples.

* Update README.

Update README with new relative links for reorg.

* Update README.md

Co-authored-by: amysteamdev <37001393+AmySteam@users.noreply.github.com>

---------

Co-authored-by: amysteamdev <37001393+AmySteam@users.noreply.github.com>

.repo/migrate-samples.js

@@ -0,0 +1,60 @@
+// Copyright 2020 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+/**
+ * @fileoverview Intended to be run as a script on the old samples page, to
+ * extract a list of samples and render as a Markdown table.
+ */
+
+var sampleHeadings = Array.from(document.querySelectorAll('main h2'));
+
+var samples = sampleHeadings2.map((heading) => {
+  const title = heading.textContent;
+
+  const link = heading.querySelector('a');
+  const href = link.href;
+
+  const expectedHrefPrefix = 'https://developer.chrome.com/extensions/examples/'
+  let id = '';
+  if (href.startsWith(expectedHrefPrefix)) {
+    id = href.substr(expectedHrefPrefix.length).replace(/\.zip$/, '');
+  } else {
+    console.warn('bad href', href);
+  }
+
+  let notes = '';
+
+  // probably a TEXT node
+  let curr = heading;
+  for (;;) {
+    curr = curr.nextSibling;
+    if (!(curr instanceof Text)) {
+      break;
+    }
+    notes += curr.textContent;
+  }
+
+  notes = notes.trim();
+  notes = notes.replace(/\s+/g, ' ');
+
+  // curr probably points to Calls: now
+
+  const callNodes = Array.from(curr.querySelectorAll('ul li code'));
+  const calls = callNodes.map((node) => node.textContent);
+
+  return {title, id, notes, calls};
+});
+
+var formatCallsList = (calls) => {
+  const parts = calls.map((call) => `<li>${call}</li>`);
+  return `<ul>${parts.join('')}</ul>`;
+};
+
+var formatRow = (sample) => {
+  return `[${sample.title}](${sample.id})<br />${sample.notes} | ${formatCallsList(sample.calls)}`;
+};
+
+var formatTable = (all) => {
+  return `Sample | Calls\n--- | ---\n${all.map(formatRow).join('\n')}`;
+};