Add golangci-lint with linters disabled

[morgo]

Part of #5503

I have added the golangci-lint'er but with all the linters that currently produce errors disabled. It will be difficult to enable them all at once, but should be achievable if we target one at a time.

Signed-off-by: Morgan Tocker tocker@gmail.com

[morgo]

Note to reviewers: this does not handle the case yet that a developer needs to rerun the bootstrap (make tools). In general we don't handle the case of developer mistakes currently, and I think that's mostly okay.. since they are a more sophisticated audience.

I changed the implementation. It will also help us get away from bootstrap.sh by downloading inside the hook.