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/tutorials/basic.rst

@@ -0,0 +1,92 @@
+##############
+Basic Tutorial
+##############
+
+Introduction
+------------
+
+This is the basic tutorial and should be used as template for other tutorials.
+
+Requirements
+------------
+
+* Arduino IDE
+* ESP32 Board
+* Good USB Cable
+
+Steps
+-----
+
+Here are the steps for this tutorial.
+
+1. Open the Arduino IDE
+
+.. figure:: ../_static/tutorials/basic/tutorial_basic_ide.png
+    :align: center
+    :width: 600
+    :alt: Arduino IDE (click to enlarge)
+    :figclass: align-center
+
+2. Build and Flash the `blink` project.
+
+Code
+----
+
+.. code-block:: arduino
+    :caption: Blink.ino
+
+    /*
+    Blink
+
+    Turns an LED on for one second, then off for one second, repeatedly.
+
+    Most Arduinos have an on-board LED you can control. On the UNO, MEGA and ZERO
+    it is attached to digital pin 13, on MKR1000 on pin 6. LED_BUILTIN is set to
+    the correct LED pin independent of which board is used.
+    If you want to know what pin the on-board LED is connected to on your Arduino
+    model, check the Technical Specs of your board at:
+    https://www.arduino.cc/en/Main/Products
+
+    modified 8 May 2014
+    by Scott Fitzgerald
+    modified 2 Sep 2016
+    by Arturo Guadalupi
+    modified 8 Sep 2016
+    by Colby Newman
+
+    This example code is in the public domain.
+
+    http://www.arduino.cc/en/Tutorial/Blink
+    */
+
+    // the setup function runs once when you press reset or power the board
+    void setup() {
+    // initialize digital pin LED_BUILTIN as an output.
+    pinMode(LED_BUILTIN, OUTPUT);
+    }
+
+    // the loop function runs over and over again forever
+    void loop() {
+    digitalWrite(LED_BUILTIN, HIGH);   // turn the LED on (HIGH is the voltage level)
+    delay(1000);                       // wait for a second
+    digitalWrite(LED_BUILTIN, LOW);    // turn the LED off by making the voltage LOW
+    delay(1000);                       // wait for a second
+    }
+
+Log Output
+----------
+
+If the log output from the serial monitor is relevant, please add here:
+
+.. code-block::
+
+    I (0) cpu_start: App cpu up.
+    I (418) cpu_start: Pro cpu start user code
+    I (418) cpu_start: cpu freq: 160000000
+
+Resources
+---------
+
+* `ESP32 Datasheet`_ (Datasheet)
+
+.. _ESP32 Datasheet: https://www.espressif.com/sites/default/files/documentation/esp32_datasheet_en.pdf