This makes the reference manual much lighter by moving
the migration guides to a separate document.
The migration guides are also reordered from last to first,
and they appear directly in the left bar, making them easier
to find in the documentation.
(From yocto-docs rev: 5121b86ee97eb62a0c69c9ad1fc0e3fabbe3e934)
Signed-off-by: Michael Opdenacker <michael.opdenacker@bootlin.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>
