devtool: add upgrade feature

devtool: add upgrade feature

Upgrades a recipe to a particular version and downloads the source code
into a folder. User can avoid patching the source code.

These are the general steps of the upgrade function:

   - Extract current recipe source code into srctree and create a branch
   - Extract upgrade recipe source code into srctree and rebase with
     previous branch. In case the rebase is not correctly applied, source
     code will not be deleted, so user correct the patches
   - Creates the new recipe under the workspace

[YOCTO #7642]

Signed-off-by: Leonardo Sandoval <leonardo.sandoval.gonzalez@linux.intel.com>
Signed-off-by: Paul Eggleton <paul.eggleton@linux.intel.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>