docs: add some support info to the sidebar

docs/_static/custom.css

@@ -57,3 +57,8 @@ dl dl pre, .admonition.note {
 div.sphinxsidebar {
     width: 250px;
 }
+
+div.support {
+    margin-top: 2em;
+    margin-bottom: 2em;
+}

docs/_templates/support.html

@@ -0,0 +1,14 @@
+<div class="support">
+    <h3>Support</h3>
+    <p>
+        Feature suggestions, new ideas, and Pull Requests are really welcome.
+        We cooperate through the
+        <a href="https://github.com/swistakm/graceful/">graceful project</a>
+        page on GitHub.
+    </p>
+    <p>
+        I you want to financially support <strong>graceful</strong> you can
+        buy a book from one of project creators:
+    </p>
+    <a target="_blank"  href="https://www.amazon.com/gp/offer-listing/1785886851/ref=as_li_tl?ie=UTF8&camp=1789&creative=9325&creativeASIN=1785886851&linkCode=am2&tag=swistakm-20&linkId=cbef4bd5d47f30abae03e1d96d9eafed"><img border="0" src="//ws-na.amazon-adsystem.com/widgets/q?_encoding=UTF8&MarketPlace=US&ASIN=1785886851&ServiceVersion=20070822&ID=AsinImage&WS=1&Format=_SL250_&tag=swistakm-20" ></a><img src="//ir-na.amazon-adsystem.com/e/ir?t=swistakm-20&l=am2&o=1&a=1785886851" width="1" height="1" border="0" alt="" style="border:none !important; margin:0px !important;" />
+</div>

docs/conf.py

@@ -84,7 +84,7 @@
         'navigation.html',
         'relations.html',
         'searchbox.html',
-        'donate.html',
+        'support.html',
     ]
 }