bitbake: toaster: added file types to the Outputs column in the build

bitbake: toaster: added file types to the Outputs column in the build

The file types are displayed in the Outputs column in the build page. The file types
are derived from the target image filenames.

[YOCTO #5947]

(Bitbake rev: 842abf6759894690d5bc770f4ea2ac15b127e5e2)

Signed-off-by: Farrell Wymore <farrell.wymore@windriver.com>
Signed-off-by: David Reyna <David.Reyna@windriver.com>
Signed-off-by: Alexandru DAMIAN <alexandru.damian@intel.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>