ISSUE #2451: Add sidebar to the documentation page

Descriptions of the changes in this PR:

This PR introduces changes for adding the sidebar to the new docusaurus based website.

### Motivation

The #2426 Pull Request introduced the changes for new docuasurus based website, However the new website still do not have sidebar similar to our current website. This PR introduces changes for adding the missing sidebar.

### Changes

Added link to the getting-started README in the _sidebars.json_.

Master Issue: #2451 

### Testing Details - 

I have build the changes locally and have verified that the sidebar is getting rendered properly. Here is the screenshot of the new sidebar - 

<img width="1680" alt="Screenshot 2020-11-28 at 12 23 28" src="https://user-images.githubusercontent.com/17764661/100495736-8d359b00-3174-11eb-853a-3d67f15dc5a4.png">


Reviewers: Nicolò Boschi <boschi1997@gmail.com>, Matteo Minardi <minardi.matteo@hotmail.it>, Enrico Olivelli <eolivelli@gmail.com>

This closes #2501 from Abhey/Issue-2451, closes #2451
diff --git a/site2/docs/getting-started.md b/site2/docs/getting-started.md
index 7381eb5..28b4737 100644
--- a/site2/docs/getting-started.md
+++ b/site2/docs/getting-started.md
@@ -1,7 +1,7 @@
 ---
 id: getting-started
 title: Latin-ish Lol
-sidebar_label: Example Page
+sidebar_label: Getting Started
 ---
 
 Check the [documentation](https://docusaurus.io) for how to use Docusaurus.
diff --git a/site2/website/pages/en/index.js b/site2/website/pages/en/index.js
index 4561821..54ddef8 100644
--- a/site2/website/pages/en/index.js
+++ b/site2/website/pages/en/index.js
@@ -45,7 +45,7 @@
                 <div className="inner">
                     <ProjectTitle/>
                     <PromoSection>
-                        <Button href={docUrl('standalone', language)}>Read the docs</Button>
+                        <Button href={docUrl('getting-started', language)}>Read the docs</Button>
                         <Button href={githubUrl()}>GitHub</Button>
                     </PromoSection>
                 </div>
diff --git a/site2/website/sidebars.json b/site2/website/sidebars.json
index 7a1d054..0612bf9 100644
--- a/site2/website/sidebars.json
+++ b/site2/website/sidebars.json
@@ -1,10 +1,19 @@
 {
   "docs": {
-    "Docusaurus": ["doc1"],
-    "First Category": ["doc2"],
-    "Second Category": ["doc3"]
-  },
-  "docs-other": {
-    "First Category": ["doc4", "doc5"]
+    "Getting Started": [
+      "getting-started"
+    ],
+    "Deployment": [
+    ],
+    "Administration": [
+    ],
+    "API":[
+    ],
+    "Security": [
+    ],
+    "Development": [
+    ],
+    "Reference":[
+    ]
   }
 }