Don't require running code in container

[itamarst]

Currently telepresence runs local code in a container. It would be even nicer if it didn't require that and code could be run normally on the developer machine directly.

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Implementation options:

• torsocks - LD_PRELOAD a library that redirects network traffic over a SOCKS proxy; the latter would be done using SSH as first pass.
• http://sshuttle.readthedocs.io/en/stable/requirements.html - this would require root, so I'm not sure I want to pursue it, but worth mentioning.

[itamarst]

Going to try to implement this next. Proposed design:

$ python myserver.py

Becomes:

$ telepresence --new-deployment go --run python myserver.py

[itamarst]

What I've discovered so far:

1. tsocks doesn't seem to work.
2. socksify doesn't seem to work.
3. torsocks does work, but only for IPs: DNS relies on custom SOCKS protocol extension that OpenSSH SOCKS proxy doesn't support (https://github.com/dgoulet/torsocks/blob/master/doc/socks/socks-extensions.txt#L40).

If I continue down this path, options are:

• Fork torsocks.
• Disable DNS-on-remote-side feature in torsocks, and figure out way to do DNS for Kubernetes Services locally. HOSTALIASES environment variable is one way, but it wouldn't support full records, e.g. "myservice" would work, but "myservices.default.svc.cluster.local" would not.
• Custom SOCKS server that implements the extra command torsocks expects.

Other issues:

• torsocks doesn't have way to set port it connects to (in older versions, e.g. one in Ubuntu 16.04) on command line. That can be worked around by having custom config file whose address is set with an env variable.

[itamarst]

Remaining work:

• Make end-to-end tests pass, in particular need to route incoming connections to IP of Docker host?
• Tests for SOCKS5 protocol implementation
• Update documentation: need torsocks, examples, ...
• Choose random free port on local machine, instead of hardcoding port 9050
• Use custom torsocks config (necessary for the above)