Updating the docs to match latest skywater-pdk.

Taken from https://github.com/google/skywater-pdk
```
commit b5ff6174d9aa921f670f12a2893969fe4a516f6c (HEAD -> main, upstream/main)
Merge: 5e159bd 73e9c84
Author: Tim Ansell <me@mith.ro>
Date:   Tue Nov 2 13:28:11 2021 -0700

    Merge pull request #341 from mithro/sphinx-theme-fix

    Update the sphinx theme
```

Signed-off-by: Tim 'mithro' Ansell <tansell@google.com>

docs/_static/favicon/browserconfig.xml

@@ -0,0 +1,9 @@
+<?xml version="1.0" encoding="utf-8"?>
+<browserconfig>
+    <msapplication>
+        <tile>
+            <square150x150logo src="/_static/favicon/mstile-150x150.png"/>
+            <TileColor>#00aba9</TileColor>
+        </tile>
+    </msapplication>
+</browserconfig>

docs/_static/favicon/html_code.html

@@ -0,0 +1,9 @@
+<link rel="apple-touch-icon" sizes="152x152" href="/_static/favicon/apple-touch-icon.png">
+<link rel="icon" type="image/png" sizes="32x32" href="/_static/favicon/favicon-32x32.png">
+<link rel="icon" type="image/png" sizes="16x16" href="/_static/favicon/favicon-16x16.png">
+<link rel="manifest" href="/_static/favicon/site.webmanifest">
+<link rel="mask-icon" href="/_static/favicon/safari-pinned-tab.svg" color="#5bbad5">
+<link rel="shortcut icon" href="/_static/favicon/favicon.ico">
+<meta name="msapplication-TileColor" content="#00aba9">
+<meta name="msapplication-config" content="/_static/favicon/browserconfig.xml">
+<meta name="theme-color" content="#ffffff">

docs/_static/favicon/site.webmanifest

@@ -0,0 +1,13 @@
+{
+    "name": "",
+    "short_name": "",
+    "icons": [
+        {
+            "src": "/_static/favicon/android-chrome-144x144.png",
+            "sizes": "144x144",
+            "type": "image/png"
+        }
+    ],
+    "theme_color": "#ffffff",
+    "background_color": "#ffffff"
+}

docs/_templates/relbar.html

@@ -0,0 +1,13 @@
+{% extends '!relbar.html' %}
+
+{%- block extralinks -%}
+{{ super() }}
+
+<li class="md-tabs__item"><a href="https://www.skywatertechnology.com/" class="md-tabs__link"><i class="md-icon">business</i> SkyWater</a></li>
+<li class="md-tabs__item"><a href="https://efabless.com/open_shuttle_program" class="md-tabs__link"><i class="md-icon">precision_manufacturing</i> Shuttle Program</a></li>
+<li class="md-tabs__item"><a href="https://join.skywater.tools/" class="md-tabs__link"><i class="md-icon">chat_bubble</i> Chat</a></li>
+<li class="md-tabs__item"><a href="https://groups.google.com/g/skywater-pdk-users" class="md-tabs__link"><i class="md-icon">campaign</i>Announcements</a></li>
+<li class="md-tabs__item"><a href="https://groups.google.com/g/skywater-pdk-users" class="md-tabs__link"><i class="md-icon">mail</i> Mailing List</a></li>
+
+
+{%- endblock -%}