Migrated Developer Docs (#5683)

- Migrated developer docs to Twenty website

- Modified User Guide and Docs layout to include sections and
subsections

**Section Example:**
<img width="549" alt="Screenshot 2024-05-30 at 15 44 42"
src="https://github.com/twentyhq/twenty/assets/102751374/41bd4037-4b76-48e6-bc79-48d3d6be9ab8">

**Subsection Example:**
<img width="557" alt="Screenshot 2024-05-30 at 15 44 55"
src="https://github.com/twentyhq/twenty/assets/102751374/f14c65a9-ab0c-4530-b624-5b20fc00511a">


- Created different components (Tabs, Tables, Editors etc.) for the mdx
files

**Tabs & Editor**

<img width="665" alt="Screenshot 2024-05-30 at 15 47 39"
src="https://github.com/twentyhq/twenty/assets/102751374/5166b5c7-b6cf-417d-9f29-b1f674c1c531">

**Tables**

<img width="698" alt="Screenshot 2024-05-30 at 15 57 39"
src="https://github.com/twentyhq/twenty/assets/102751374/2bbfe937-ec19-4004-ab00-f7a56e96db4a">

<img width="661" alt="Screenshot 2024-05-30 at 16 03 32"
src="https://github.com/twentyhq/twenty/assets/102751374/ae95b47c-dd92-44f9-b535-ccdc953f71ff">

- Created a crawler for Twenty Developers (now that it will be on the
twenty website). Once this PR is merged and the website is re-deployed,
we need to start crawling and make sure the index name is
‘twenty-developer’
- Added a dropdown menu in the header to access User Guide and
Developers + added Developers to footer


https://github.com/twentyhq/twenty/assets/102751374/1bd1fbbd-1e65-4461-b18b-84d4ddbb8ea1

- Made new layout responsive

Please fill in the information for each mdx file so that it can appear
on its card, as well as in the ‘In this article’ section. Example with
‘Getting Started’ in the User Guide:

<img width="786" alt="Screenshot 2024-05-30 at 16 29 39"
src="https://github.com/twentyhq/twenty/assets/102751374/2714b01d-a664-4ddc-9291-528632ee12ea">

Example with info and sectionInfo filled in for 'Getting Started':

<img width="620" alt="Screenshot 2024-05-30 at 16 33 57"
src="https://github.com/twentyhq/twenty/assets/102751374/bc69e880-da6a-4b7e-bace-1effea866c11">


Please keep in mind that the images that are being used for Developers
are the same as those found in User Guide and may not match the article.

---------

Co-authored-by: Félix Malfait <felix.malfait@gmail.com>

packages/twenty-website/src/content/user-guide/getting-started/what-is-twenty.mdx

@@ -0,0 +1,71 @@
+---
+title: What is Twenty
+icon: IconUsers
+info: Discover Twenty, an open-source CRM, its features, benefits, system requirements, and how to get involved.
+image: /images/user-guide/what-is-twenty/20.png
+sectionInfo: Discover Twenty, an open-source CRM.
+---
+
+## Overview
+
+Twenty is the leading open-source CRM, crafted by hundreds of contributors to suit your unique business needs.
+
+### Main Features
+
+**Contact Management:** Efficiently store and manage customer data. [Learn more](/user-guide/objects).
+
+**Custom Objects:** Create and customize objects to fit your business needs. [Details](/user-guide/objects).
+
+**Custom Fields:** Tailor data fields to capture and organize information specific to your operations. [Understand more](/user-guide/fields).
+
+**Kanban & Table Views:** Optimize your workflow with flexible [Table Views](/user-guide/table-views) and [Kanban Views](/user-guide/kanban-views).
+
+**Pipeline Visualization:** Get a clear view of your processes with customizable views. [Explore views](/user-guide/views-sort-and-filter).
+
+**Email Integration:** View the emails of a specific customer or company within your workspace. [Integrate now](/user-guide/emails).
+
+**Notes:** Create detailed notes for each record to share knowledge more effectively. [Add notes](/user-guide/notes).
+
+**Tasks:** Schedule tasks to track customer interactions. [See how](/user-guide/tasks).
+
+**API & Webhooks:** Connect to other apps and automate workflows with API and Webhooks. [Start integrating](/user-guide/integrations).
+
+### Benefits
+
+**Customizable:** Designed to fit your business needs.
+
+**Community-driven:** Built and maintained by a large open-source community.
+
+**Cost-effective:** You'll never be vendor-locked because can always self-host.
+
+### System Requirements
+
+Modern web browser (Firefox, Chrome, Safari and Edge on their latest version are supported).
+
+Internet connection (Offline mode isn't yet supported).
+
+## Demo
+
+If you wish to try Twenty before creating your own account, go to demo.twenty.com and login with the following credentials:
+
+
+`email: noah@demo.dev`\
+`password: Applecar2025`
+
+## Vision
+Creating a good CRM is hard because it's a balancing act.
+For each business, the requirements seem straightforward, yet everyone's needs are distinct.
+The result is a CRM that's either too basic, or one that's attempting to be a jack-of-all-trades but ending up as a master of none.
+
+At first, Twenty looks like most CRMs you already know: you can track deals, organize contacts, manage tasks and notes.
+But what sets it apart is our approach to extensibility. We are building an open platform that provides the building blocks for you to solve your unique business problems.
+
+We prioritize universal principles and common patterns over feature lists. 
+We don't try to have all the answers and instead empower users to find what works best for them.
+And Open-source is the bedrock of our approach, ensuring that Twenty evolves with its community, for its community.
+
+## Join now
+
+<ArticleLink href="https://app.twenty.com">Register here</ArticleLink> or <ArticleLink href="https://github.com/twentyhq/twenty">become a contributor on GitHub</ArticleLink>.
+
+<ArticleEditContent articleTitle="what-is-twenty.mdx"></ArticleEditContent>