support/scripts/pkg-stats: add package status

support/scripts/pkg-stats: add package status

Unify the status check information. The status is stored in a tuple. The
first entry is the status that can be 'ok', 'warning' or 'error'. The
second entry is a verbose message.

The following checks are performed:
- url: status of the URL check
- license: status of the license presence check
- license-files: status of the license file check
- hash: status of the hash file presence check
- patches: status of the patches count check
- pkg-check: status of the check-package script result
- developers: status if a package has developers in the DEVELOPERS file
- version: status of the version check

With that status information the following variables are replaced:
has_license, has_license_files, has_hash, url_status

Signed-off-by: Heiko Thiery <heiko.thiery@gmail.com>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>