fix the mounted local storage permission issue for the docker release

[wisicn]

Description

add the capability to specific the UID and GID of the local storage which will be mounted to the docker container by -v.

if we don't specify the UID and GID, there will be a lot of issues like Permission denied: '/home/mitmproxy/.mitmproxy/mitmproxy-ca.pem' in this issue #6

[mhils]

Could you please explain why this is necessary? We do chown -R mitmproxy:mitmproxy ~/.mitmproxy in our entrypoint, which should resolve all permission errors.

[mhils]

Superseded by https://github.com/mitmproxy/mitmproxy/pull/5550