recipeutils: add optional stable_upgrade parameter to get_recipe_upgrade_status

recipeutils: add optional stable_upgrade parameter to get_recipe_upgrade_status

We want the ability to do stable version upgrades for recipes.
To this end, add an optional stable_upgrade parameter to the
get_recipe_upgrade_status function, which defaults to False and
when enabled will try to get the latest stable version of the recipe.

The UPSTREAM_STABLE_RELEASE_REGEX is respected. If a recipe sets
it, it will be used as the filter_regex. If it's not set explicitly,
it means that there's no stable updates or the recipe hasn't been
checked yet.

Signed-off-by: Chen Qi <Qi.Chen@windriver.com>
Signed-off-by: Antonin Godard <antonin.godard@bootlin.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>