Docs: Initial documentation structure using Sphinx (#5355)

This PR is the initial documentation structure including the basic information about the project and Sphinx configuration.

####CONTENTS:
- Getting Started
- Installing
- Boards
- Libraries
- Library Builder
- Tutorials
- ESP-IDF as Component
- OTA Web Update
- makeEspArduino
- Troubleshooting
- Contributing

This PR also changes the README.md.

docs/source/boards/boards.rst

@@ -0,0 +1,106 @@
+######
+Boards
+######
+
+Development Boards
+------------------
+
+You will need a development board or a custom board with the ESP32 (see Supported SoC's) to start playing.
+There is a bunch of different types and models widely available on the Internet. You need to choose one that covers all your requirements.
+
+To help you on this selection, we point out some facts about choosing the proper boardsto help you to save money and time.
+
+**One ESP32 to rule them all!**
+
+One important information that usually bring about some confusion is regarding the different models of the ESP32 SoC and modules.
+
+The ESP32 is divided by family:
+
+* ESP32
+    * Wi-Fi and BLE
+* ESP32-S
+    * Wi-Fi only
+* ESP32-C
+    * Wi-Fi and BLE 5
+
+For each family, we have SoC variants with some differentiation. The differences are more about the embedded flash and its size and the number of the cores (dual or single).
+
+The modules use the SoC internally, including the external flash, PSRAM (in some models) and other essential electronic components. Essentially, all
+modules from the same family use the same SoC.
+
+.. figure:: ../_static/soc-module.png
+    :align: center
+    :width: 250
+    :alt: ESP32 SoC and Module (click to enlarge)
+    :figclass: align-center
+
+**For example:**
+
+The SoC partnumber is the ESP32-D0WD-V3 and it's the same SoC used inside of the ESP32-WROVER (with PSRAM) and ESP32-WROOM modules. This means that the
+same characteristics are present in both modules' core.
+
+For more detailed information regarding the SoC's and modules, see the `Espressif Product Selector`_.
+
+Now that you know that the module can be different but the heart is the same, you can choose your development board.
+
+Before buying: Keep in mind that for some "must have" features when choosing the best board for your needs:
+
+- Embedded USB-to-Serial
+    - This is very convenient for programming and monitoring the logs with the terminal via USB. 
+- Breadboard friendly
+    - If you are prototyping, this will be very useful to connect your board directly on the breadboard.
+- open-source/open-hardware
+    - Check if the schematics are available for download. This helps a lot on prototyping.
+- Support
+    - Some of the manufacturers offer a very good level of support, with examples and demo projects.
+
+
+Espressif
+---------
+
+.. figure:: ../_static/logo_espressif.png
+    :align: center
+    :width: 250
+    :alt: Espressif Logo
+    :figclass: align-center
+
+.. toctree::
+    :maxdepth: 1
+
+    ESP32-DevKitC <ESP32-DevKitC-1>
+    ESP32-S2-Saola-1 <ESP32-S2-Saola-1>
+    ESP32-C3-DevKitM-1 <ESP32-C3-DevKitM-1>
+
+Third Party
+-----------
+
+Add here the third party boards, listed by vendors.
+
+.. note::
+    All the information must be provided by the vendor. If your favorite board is not here, consider
+    creating an `issue on GitHub <https://github.com/espressif/arduino-esp32/issues>`_ and directly
+    link/mention the vendor in the issue description.
+
+Generic Vendor
+**************
+
+.. toctree::
+    :maxdepth: 1
+
+    Generic Board Name <generic>
+
+.. note::
+    Create one file per board or one file with multiple boards. Do not add board information/description on this file.
+
+Resources
+---------
+
+* `ESP32 Datasheet`_ (Datasheet)
+* `ESP32-S2 Datasheet`_ (Datasheet)
+* `ESP32-C3 Datasheet`_ (Datasheet)
+
+.. _Espressif Systems: https://www.espressif.com 
+.. _Espressif Product Selector: https://products.espressif.com/
+.. _ESP32 Datasheet: https://www.espressif.com/sites/default/files/documentation/esp32_datasheet_en.pdf
+.. _ESP32-S2 Datasheet: https://www.espressif.com/sites/default/files/documentation/esp32-s2_datasheet_en.pdf
+.. _ESP32-C3 Datasheet: https://www.espressif.com/sites/default/files/documentation/esp32-c3_datasheet_en.pdf