update dockerfile and use openssl

[Stebalien]

This PR:

• Updates docker deps (go -> 1.13.5, tini -> 0.18.0)
• Builds go-ipfs using openssl. We don't distribute go-ipfs with OpenSSL support by default to avoid depending on external libraries. However, we completely control the docker environment so there's no reason not to build with OpenSSL support. This significantly reduces CPU usage.
• Explicitly set the permissions on start_ipfs so we don't inherit the defaults set by the host OS.

[olizilla]

Note: I think moving this to the first line means we'll have to explicitly run with --no-cache=true when we want to re-update those dependencies. The layer cache uses the string value of the RUN command to see if already has a layer for that.

aside from the ADD and COPY commands, cache checking does not look at the files in the container to determine a cache match. For example, when processing a RUN apt-get -y update command the files updated in the container are not examined to determine if a cache hit exists. In that case just the command string itself is used to find a match.

https://docs.docker.com/develop/develop-images/dockerfile_best-practices/#leverage-build-cache

[Stebalien]

That's probably for the best, actually. When rebuilding, we usually just want to update ipfs itself.

[olizilla]

👍 ran it locally, it still blends.