chore: customize <title> and add new <meta> description tag (#1719)

Author: lauzadis

docs/dokka-presets/templates/includes/page_metadata.ftl

@@ -0,0 +1,8 @@
+<#-- Copied from Dokka, customized for SEO: https://github.com/Kotlin/dokka/blob/3cc0b61498877f8e9025c1260f967f7e4236b301/dokka-subprojects/plugin-base/src/main/resources/dokka/templates/includes/page_metadata.ftl -->
+<#macro display>
+    <title>${pageName} - AWS SDK for Kotlin</title>
+    <meta name="description" content="Learn how to use ${pageName} in the AWS SDK for Kotlin">
+    <@template_cmd name="pathToRoot">
+        <link href="${pathToRoot}images/logo-icon.svg" rel="icon" type="image/svg">
+    </@template_cmd>
+</#macro>