- injects a mitmproxy between the caching layer and DockerHub's registry-1.docker.io
- it also disables VERIFY_SSL so the mitmproxy can be used;
- DEBUG_HUB's mitmweb is exposed on port 8082
- both DEBUG and DEBUG_HUB can be enabled independently
- now only /v2/.../blobs/... URIs are actually cached (together with their redirect catchers)
- /manifests/, /token, and /v2/ are not cached anymore, which should solve a lot of problems
- better messages for /v1 attempts
- fix usage of $connect_host:443 (which is hostname:port and causes errors to be logged) to $connect_addr (which returns an IP:port) in the proxy layer