inspektor.check: Add new check_patch_github API

That will be used by the inspektor app.

Signed-off-by: Lucas Meneghel Rodrigues <lmr@redhat.com>
inspektor.cli.app: Implement github subcommand

Usage:

inspekt github [PR number]

Signed-off-by: Lucas Meneghel Rodrigues <lmr@redhat.com>
inspektor.check: Look in vcs.cwd the license name
inspektor.utils: Make download and process accessible
inspektor.utils.download: Make get_file to return retrieved filename
inspektor.vcs: Fix incorrect variable reference

Signed-off-by: Lucas Meneghel Rodrigues <lmr@redhat.com>