Support encoded Content-Disposition fields

Closes #207

See merge request gitlab-org/gitlab-workhorse!360

https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/24919/diffs adds
support for Rails sending the right `Content-Disposition` header when
there are non-ASCII filenames (e.g. `テスト.txt`). That example file
would render the following Content-Disposition:

```
attachment; filename="テスト.txt", filename*=UTF-8''%E3%83%86%E3%82%B9%E3%83%88.txt
```

Since mime.ParseMediaType appears to strip this header to a canonical
filename, it's not possible to use this to generate the right
Content-Disposition. Instead, we can preserve the existing
Content-Disposition and convert types just by doing a search and replace
(i.e. change `attachment` to `inline` and vice versa when necessary).

Closes https://gitlab.com/gitlab-org/gitlab-workhorse/issues/207

Count ^/-/ requests separately in prometheus

Closes #204

See merge request gitlab-org/gitlab-workhorse!355

Statically link jaeger into Workhorse by default

See merge request gitlab-org/gitlab-workhorse!359

This change will statically compile the jaeger client into workhorse
by default. This will allow support staff to enable the
`GITLAB_TRACING` variable to investigate issues further.

Note that by default, this will not enable tracing, only compile the
client in.

Release v8.2.0

See merge request gitlab-org/gitlab-workhorse!358

Sync master with the recent security release

See merge request gitlab-org/gitlab-workhorse!356

This is a necessary change to solve a security issue. For more details,
see this issue: https://gitlab.com/gitlab-org/gitlab-workhorse/issues/197

Fix SVG recognition to get the proper content type

See merge request gitlab-org/gitlab-workhorse!353

Avoid an ambiguously formattable directive

See merge request gitlab-org/gitlab-workhorse!354

Changelog for 8.1.0

See merge request gitlab-org/gitlab-workhorse!352

Add distributed tracing with LabKit

See merge request gitlab-org/gitlab-workhorse!325

Upgrade the gitaly client

See merge request gitlab-org/gitlab-workhorse!351

Support for TLS is now included.

Upgrade Gitaly Proto to use gitalypb

See merge request gitlab-org/gitlab-workhorse!331

This is a version than includes the new gitaly-proto, which has the
package name changed. Now gitalypb is used everywhere. The client of
Gitaly is updated too, as only one proto definition can register a type.

Release v8.0.0

See merge request gitlab-org/gitlab-workhorse!350

Remove local git format-patch handling

See merge request gitlab-org/gitlab-workhorse!346

Remove local git diff handling

See merge request gitlab-org/gitlab-workhorse!345

Back-port changelog from 7-5-stable

See merge request gitlab-org/gitlab-workhorse!349

Remove local git archive support

Closes #166

See merge request gitlab-org/gitlab-workhorse!304

Changelog for 7.6.0

See merge request gitlab-org/gitlab-workhorse!347

Remove local git receive-pack implementation

See merge request gitlab-org/gitlab-workhorse!326

Rename correlation-id structured logging field to correlation_id

See merge request gitlab-org/gitlab-workhorse!343