README.md: Consolidate WSL specific instructions

Move all of the documentation specific to the WSL kernel into README.md.
The README.md file is displayed in the GitHub web interface in favor of
the upstream README file.

Leave a symlink from README-Microsoft.WSL2 to README.md so that anyone
watching that file for changes will continue to see updates.

While consolidating documentation, clean up trailing spaces and adjust
the build dependency installation instructions to include the missing
apt command.

Signed-off-by: Tyler Hicks <[email protected]>

Author: tyhicks

README

@@ -16,24 +16,3 @@ several of them using the Restructured Text markup notation.
 Please read the Documentation/process/changes.rst file, as it contains the
 requirements for building and running the kernel, and information about
 the problems which may result by upgrading your kernel.
-
-============
-
-The WSL 2 Linux kernel repo provides the additional infrastructure necessary 
-to build and release the kernel component of WSL 2. It was never designed to 
-replace the current existing community and feedback channels for WSL, 
-especially through: https://github.com/microsoft/WSL. This is why we are not 
-accepting issues or pull requests through this repository.
- 
-If you have an issue relating to WSL, or the WSL 2 Linux kernel configuration, 
-please report it at the WSL GitHub: would like contribute to or report an issue 
-on the WSL2 kernel, please do so at the WSL GitHub:
-
-https://github.com/microsoft/WSL/issues/new/choose 
- 
-The WSL 2 Linux kernel is based on the Linux version from 
-https://www.kernel.org/. If you would like to contribute to or report an issue 
-on the Linux kernel in general, please do so on the upstream Linux GitHub:  
-
-https://www.kernel.org/doc/html/latest/process/submitting-patches.html
-

README-Microsoft.WSL2

@@ -0,0 +1 @@
+README.md

README-Microsoft.WSL2

@@ -0,0 +1,25 @@
+= Introduction =
+
+The WSL 2 Linux kernel repo provides the additional infrastructure necessary
+to build and release the kernel component of WSL 2. It was never designed to
+replace the current existing community and feedback channels for WSL,
+especially through: https://github.com/microsoft/WSL. This is why we are not
+accepting issues or pull requests through this repository.
+
+If you have an issue relating to WSL, or the WSL 2 Linux kernel configuration,
+please report it at the WSL GitHub: would like contribute to or report an issue
+on the WSL2 kernel, please do so at the WSL GitHub:
+
+https://github.com/microsoft/WSL/issues/new/choose
+
+The WSL 2 Linux kernel is based on the Linux version from
+https://www.kernel.org/. If you would like to contribute to or report an issue
+on the Linux kernel in general, please do so on the upstream Linux GitHub:
+
+https://www.kernel.org/doc/html/latest/process/submitting-patches.html
+
+= Build Instructions =
+
+1. Install a recent Ubuntu distribution
+2. sudo apt install build-essential flex bison libssl-dev libelf-dev
+3. make KCONFIG_CONFIG=Microsoft/config-wsl