doc: move README.log to HTML documentation

Convert README.log to reStructuredText and add it to the generated HTML
documentation.

Assign doc/develop/logging.rst to the maintainer of LOGGING.

Signed-off-by: Heinrich Schuchardt <xypron.glpk@gmx.de>
Reviewed-by: Simon Glass <sjg@chromium.org>
diff --git a/doc/develop/index.rst b/doc/develop/index.rst
index 072db63..eb5095a 100644
--- a/doc/develop/index.rst
+++ b/doc/develop/index.rst
@@ -8,3 +8,4 @@
    :maxdepth: 2
 
    crash_dumps
+   logging