docs-rst: create a book for the development process

Now that the files at Documentation/development-process/
were converted to ReST, make create a book at Sphinx.

As we'll have other books related to the development process,
we'll add it as a sub-book.

Signed-off-by: Mauro Carvalho Chehab <[e-mail]>
Signed-off-by: Jonathan Corbet <[e-mail]>

Documentation/conf.py

···
 latex_documents = [
     ('kernel-documentation', 'kernel-documentation.tex', 'The Linux Kernel Documentation',
      'The kernel development community', 'manual'),
+    ('development-process/index', 'development-process.tex', 'Linux Kernel Development Documentation',
+     'The kernel development community', 'manual'),
     ('gpu/index', 'gpu.tex', 'Linux GPU Driver Developer\'s Guide',
      'The kernel development community', 'manual'),
 ]

Documentation/development-process/conf.py

···
+# -*- coding: utf-8; mode: python -*-
+
+project = 'Linux Kernel Development Documentation'
+
+tags.add("subproject")
+
+latex_documents = [
+    ('index', 'development-process.tex', 'Linux Kernel Development Documentation',
+     'The kernel development community', 'manual'),
+]

Documentation/development-process/index.rst

···
+Linux Kernel Development Documentation
+======================================
+
+Contents:
+
+.. toctree::
+   :maxdepth: 2
+
+   development-process

Documentation/index.rst

···
    :maxdepth: 2
 
    kernel-documentation
+   development-process/index
    dev-tools/tools
    driver-api/index
    media/index