Add new endpoint to add support to proxy websocket requests to build's services

Closes #205 and gitlab-ee#5276

See merge request gitlab-org/gitlab-workhorse!370

In this MR we add two endpoints for proxying requests
to services running inside the runner's builds.

One of the endpoints is for regular HTTP requests, while
the other is for websockets.

Release v8.5.1

See merge request gitlab-org/gitlab-workhorse!387

Remove duplicate X-Request-Id response header

Closes gitlab-ce#60111

See merge request gitlab-org/gitlab-workhorse!384

This fixes performance bar not working with AJAX requests.

Both LabKit and Rails were injecting duplicate X-Request-Id headers into
the response stream, which caused the frontend to be interpret the value
as a comma-separated value (e.g. LdEgVXsp1R4, LdEgVXsp1R4).

The new flow behaves as the following:

1. Workhorse injects X-Request-Id to the inbound HTTP request to Rails
2. Rails looks up this value in its RequestId middleware. Since the
value exists, Rails sets the X-Request-Id response header to this value.
3. Workhorse doesn't append another header in the response.

Distributed tracing should still work fine because Workhorse still
generates the correlation ID.

Closes https://gitlab.com/gitlab-org/gitlab-ce/issues/60111

Release v8.5.0

See merge request gitlab-org/gitlab-workhorse!383

Replace terminal terminology to channel

See merge request gitlab-org/gitlab-workhorse!382

We're moving from using terminology related to terminal when
we refer to websockets connections. It's more generalistic
a concept like channel.

Release v8.4.0

See merge request gitlab-org/gitlab-workhorse!381

Add code from the most recent security release to master

See merge request gitlab-org/gitlab-workhorse!380

EXIF may contain sensitive information, when uploading
any file which may be an image (based on filename suffix),
we run it through exiftool which removes any metadata.

Get git-archive with GetArchiveRequest

See merge request gitlab-org/gitlab-workhorse!375

Update release process

See merge request gitlab-org/gitlab-workhorse!378

Parse the GetArchiveRequest from the send data header and
use it when making calling the GetArchive RPC on gitaly.

In order for this to work, gitaly-proto needs to be updated.

The protobuf/proto packages needs to be updated as a requirement
of gitaly-proto. Updated it to the same version as gitaly.

Shorten error messages to D&K style

See merge request gitlab-org/gitlab-workhorse!377

Replace megacheck with staticcheck

Closes #212

See merge request gitlab-org/gitlab-workhorse!376

Includes some fixes on some files based on suggestion of
`staticcheck`.

Bumps the default go image to 1.11 from 1.10. Still run 1.10
on `test using go 1.10` job.

Prepare for Gitaly absorbing gitlab-shell hooks

Closes #211

See merge request gitlab-org/gitlab-workhorse!374

Filter `sharedSecret` param from Jira

See merge request gitlab-org/gitlab-workhorse!369

Upgrade Gitaly-Proto to protobuf go v1.2 code

See merge request gitlab-org/gitlab-workhorse!368

Helps determine the state of
https://gitlab.com/gitlab-org/gitaly-proto/merge_requests/266

Allow unknown fields in jsonpb gitaly-proto messages

Closes gitlab-ce#57589

See merge request gitlab-org/gitlab-workhorse!367

Change content type detection header size to 4k

See merge request gitlab-org/gitlab-workhorse!366

There is a problem detecting some file types like SVG. Depending
on how the file is built, it will detect the right content type
or not. For example, if the SVG file has a big html comment
(more than 512 bytes) at the beginning of it, when we start
the detection process we'll get the first 512 bytes and based on
that we will set the content type `text/plain`. But this is wrong
because the file is indeed an SVG.

Update gitaly-proto to v1.10.0

See merge request gitlab-org/gitlab-workhorse!364