recipetool: create: support creation of additional files by plugins
Allow plugins to create additional files to go alongside the recipe. The
plugins don't know what the output filename is going to be, so they need
to put the files in a temporary location and add them to an "extrafiles"
dict within extravalues where the destination filename is the key and
the temporary path is the value.
devtool add was also extended to ensure these files get moved in and
preserved upon reset if they've been edited by the user.
Signed-off-by: Paul Eggleton <paul.eggleton@linux.intel.com> Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>
