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.

* DOCUMENTATION: Moved installation instructions to separate page

* Added Fedora to contents table
* Added Issue/Bug Report section to README
* Some minor improvements

* DOCUMENTATION: Rename directory doc to docs

* Also move ISSUE_TEMPLATE.md to docs directory

* DOCUMENTATION: Use current repo's files

* This makes it consistent instead  of having few local and few pointing to
  espressif/arduino-esp32 by all linking to local files

* DOCUMENTATION: Fix hyperlink to issue/bug template in contents

* DOCUMENTATION: contents: supress platform specific installation instruction

With this step we remove all dependencies, but git. Mac and Linux come
with Python by default, so they will keep using get.py to update the
toolchain and support binaries. Windows users have an "All point and
click" installation option that requires only git and Arduino to be
downloaded.
Fingers crossed :)