Setup project for docs build with new Dokka

- Update Dokka to 1.6.20-M1
- Update Dokka to 1.6.20
- Update Dokka to 1.7.0-dev
- Update Dokka to 1.7.20-dev-187

Co-authored-by: ilya.gorbunov@jetbrains.com

libraries/tools/kotlin-stdlib-docs/templates/includes/footer.ftl

@@ -0,0 +1,7 @@
+<#macro display>
+      <div class="footer">
+        <span class="go-to-top-icon"><a href="#content" id="go-to-top-link"></a></span><span>${footerMessage}</span><span
+                class="pull-right"><span>Generated by </span><a
+                href="https://github.com/Kotlin/dokka"><span>dokka</span><span class="padded-icon"></span></a></span>
+      </div>
+</#macro>

libraries/tools/kotlin-stdlib-docs/templates/includes/header.ftl

@@ -0,0 +1,24 @@
+<#import "source_set_selector.ftl" as source_set_selector>
+<#macro display>
+<div class="navigation-wrapper" id="navigation-wrapper">
+    <div id="leftToggler"><span class="icon-toggler"></span></div>
+    <div class="library-name">
+        <@template_cmd name="pathToRoot">
+            <a href="${pathToRoot}index.html">
+                <@template_cmd name="projectName">
+                    <span>${projectName}</span>
+                </@template_cmd>
+            </a>
+        </@template_cmd>
+    </div>
+    <div>
+        <#-- This can be handled by a versioning plugin -->
+        <@version/>
+    </div>
+    <div class="pull-right d-flex">
+        <@source_set_selector.display/>
+        <button id="theme-toggle-button"><span id="theme-toggle"></span></button>
+        <div id="searchBar"></div>
+    </div>
+</div>
+</#macro>

libraries/tools/kotlin-stdlib-docs/templates/includes/page_metadata.ftl

@@ -0,0 +1,6 @@
+<#macro display>
+    <title>${pageName}</title>
+    <@template_cmd name="pathToRoot">
+    <link href="${pathToRoot}images/logo-icon.svg" rel="icon" type="image/svg">
+    </@template_cmd>
+</#macro>