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.

Typos fixed and added more details and instructions
Added README file to WiFiScan example
Review on the README template
Added link to DevKits

Board images updated and added warning on Flash/PSRAM pins

* Update debian_ubuntu.md

ERROR: This script does not work on Python 2.7 The minimum supported Python version is 3.6. Please use https://bootstrap.pypa.io/2.7/get-pip.py instead.

* Update debian_ubuntu.md
Co-authored-by: NMe No Dev <me-no-dev@users.noreply.github.com>

Closes #4111.
gcc: I was not able to find an arm64 build on espressif's website so I choosed to put the armhf version, even if this should works this is only ok as temporary, arm64 runs better on arm64 than armhf :)
esptool: being interpreted python its ok
mkspiff: need igrr/mkspiffs#74 to be merged and artifacts added in /package/package_esp32_index.template.json.

Make options list into a table

shallow clone (board and submodules) to make installation faster

* Docs for lib builder

* Typos and such

more secure

Executing python2 get.py behind proxy give error "IOError: [Errno socket error] [SSL: UNKNOWN_PROTOCOL] unknown protocol (_ssl.c:590)"

(removed quotes from last line, and fixed indentation, no text changes)

* Updated ISSUE_TEMPLATE to try to get better postings

* Added line for PSRAM enabled

* More complete info request as per @stickbreaker

add a troubleshooting hint

* Added instructions for installation with boards manager (stolen directly from esp8266)

* changed to production link instead of dev

* Added to main README. Made mods to images as requested.

* Added links for development package

* Moved version images to README.md

* Just a little change for cleaner look

* Cleaned up README.md and boards_manager.md to make installation easier.

* Added instructions for installation with boards manager (stolen directly from esp8266)

* changed to production link instead of dev

* Added to main README. Made mods to images as requested.

* Added links for development package

As discussed in #1042.

adding an additional step that is required to make sure the BLE libs are synced

Usable for library developers who write code not dependent on Arduino.
Adding 3 lines to the includes will permit their debug messages to be
visible in Arduino IDE or when enabled under IDF

* Update IDF to de750e9

* Add BLE Library submodule