docs: livepatch: convert docs to ReST and rename to *.rst

Convert livepatch documentation to ReST format. The changes
are mostly trivial, as the documents are already on a good
shape. Just a few markup changes are needed for Sphinx to
properly parse the docs.

The conversion is actually:
  - add blank lines and identation in order to identify paragraphs;
  - fix tables markups;
  - add some lists markups;
  - mark literal blocks;
  - The in-file TOC becomes a comment, in order to skip it from the
    output, as Sphinx already generates an index there.
  - adjust title markups.

At its new index.rst, let's add a :orphan: while this is not linked to
the main index.rst file, in order to avoid build warnings.

Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>
Signed-off-by: Petr Mladek <pmladek@suse.com>
Acked-by: Miroslav Benes <mbenes@suse.cz>
Acked-by: Josh Poimboeuf <jpoimboe@redhat.com>
Acked-by: Joe Lawrence <joe.lawrence@redhat.com>
Reviewed-by: Kamalesh Babulal <kamalesh@linux.vnet.ibm.com>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>