Documentation (#769)

* spelling correction

* Restuctured, added "features", "supported hardware", intro for developers and links to the developer documentation.

* Spelling correction

* URL correction

* Documentation restructure

* Moving developer documentation index from top level README to Documentation directory README

* fixing URLS

* Restructuring and adding to board config

* Improving navigation of docs oon github

* New line after first heading

(https://github.com/home-assistant/operating-system/pull/768#discussion_r453336692)

Co-authored-by: Franck Nijhof <frenck@frenck.nl>

* Update README.md

https://github.com/home-assistant/operating-system/pull/768#discussion_r453336871

Co-authored-by: Franck Nijhof <frenck@frenck.nl>

* Update README.md

(https://github.com/home-assistant/operating-system/pull/768#discussion_r453336999)
- Surround headings with newlines
- ODROID
- Use dashes for unordered lists

Co-authored-by: Franck Nijhof <frenck@frenck.nl>

* Update README.md

- new line after heading
(https://github.com/home-assistant/operating-system/pull/768#discussion_r453337043)

Co-authored-by: Franck Nijhof <frenck@frenck.nl>

* Update README.md

- \- for unordered lists
- new line after heading
(https://github.com/home-assistant/operating-system/pull/768#discussion_r453337101)

Co-authored-by: Franck Nijhof <frenck@frenck.nl>

* Update README.md

- new line after heading
- \- for unordered lists
(https://github.com/home-assistant/operating-system/pull/768#discussion_r453337183)

Co-authored-by: Franck Nijhof <frenck@frenck.nl>

* Spelling correction, to ensure /Dpcumentation/kernel.mdhas the correct spelling

* capitalisation

* using - for unordered lists

* Adding links to config files

* fixing links to _defconfig files

* fixing link for rpi0_w

* fixing link for rpi3_64 and rpi4_64

* making the ova README consistent with the others

* formmating

* fixing numbered list

* fixing indent for sub-bullets

* questions regarding Tinker S and OVA support

* resolving PR comment from fabaff

* resolving PR comment from fabaff

* https://github.com/home-assistant/operating-system/pull/769\#discussion_r456774209

* Changing uBoot to U-Boot (https://github.com/home-assistant/operating-system/pull/769#discussion_r456774290)

* s/boot sector/eMMC boot partition/ (See https://github.com/home-assistant/operating-system/pull/769#discussion_r456774329)

* As per comments here:
https://github.com/home-assistant/operating-system/pull/769#discussion_r456791491
https://github.com/home-assistant/operating-system/pull/769#discussion_r456791580

* HassOS is no longer the official name (https://github.com/home-assistant/operating-system/pull/769#discussion_r456791863)

* Should be Home Assistant Operating System (or OS) (see https://community.home-assistant.io/t/changing-the-home-assistant-brand/167500/16). See also commennts here https://github.com/home-assistant/operating-system/pull/769#discussion_r456793030, taken in to account along with previous comments about this paragraph.

* s/HassOS/Home Assistant Operating System/

* 8Gb Pi 4 will be supported soon (see comment https://github.com/home-assistant/operating-system/pull/769#discussion_r459768349)

* resolving conflict with main dev branch.

Co-authored-by: Franck Nijhof <frenck@frenck.nl>
Co-authored-by: Pascal Vizeli <pvizeli@syshack.ch>

Documentation/boards/intel/README.md

@@ -0,0 +1,56 @@
+# Intel NUC
+
+## Supported Hardware
+
+This board configuration supports the Intel NUC mini PCs and compatibles. It should work for most recent NUC computers and, because this is a UEFI based image, it should in fact work with for any x86-64 based computer with UEFI. Hardware it has been tested with is listed below.
+
+## Tested Hardware
+
+| Device                | Release Date | Support | Config      |
+|-----------------------|--------------|---------|-------------|
+| Intel NUC5CPYH        | Q3 2015      | yes     | [intel_nuc](../../../buildroot-external/configs/intel_nuc_defconfig) |
+| Intel NUC6CAYH        | Q4 2016      | yes     | [intel_nuc](../../../buildroot-external/configs/intel_nuc_defconfig) |
+| Intel NUC10i3FNK2     | Q4 2019      | yes     | [intel_nuc](../../../buildroot-external/configs/intel_nuc_defconfig) |
+| Gigabyte GB-BPCE-3455 | 2017         | yes*    | [intel_nuc](../../../buildroot-external/configs/intel_nuc_defconfig) |
+
+\* needs 'nomodeset' in cmdline.txt if you want a console
+
+
+## Requirements
+
+- x86-64 support
+- UEFI boot
+- SATA/AHCI storage
+- Supported NIC:
+  - Intel Gigabit NIC (e1000, igb - via Linux mainline)
+  - Intel PCIe Gigabit NIC (e1000e - via out-of-tree module in *buildroot-external/package/intel-e1000e*)
+  - Realtek Gigabit NIC (r8169)
+  - Intel Wireless Wifi 802.11ac (iwlwifi, see below)
+
+## Wifi
+
+The following cards are supported:
+
+- Intel Wireless 3160
+- Intel Wireless 7260
+- Intel Wireless 7265
+- Intel Wireless-AC 3165
+- Intel Wireless-AC 3168
+- Intel Wireless-AC 8260
+- Intel Wireless-AC 8265
+- Intel Wireless-AC 9260
+- Intel Wireless-AC 9461
+- Intel Wireless-AC 9462
+- Intel Wireless-AC 9560
+
+## Bluetooth
+
+Bluetooth is untested.
+
+## Installation
+
+Currently there is no shiny installation method. Checklist:
+- Boot PC to live-environment using PXE or USB
+- Copy or download the hassos image into your live environment
+- zcat the image to local harddisk
+- Reboot