GitLab

This update is done in preparation for importing the Go Cloud SDK.  To
fix this properly, we will have to update Gitaly to use Protobuf v2:
https://blog.golang.org/protobuf-apiv2

See https://gitlab.com/gitlab-org/gitlab-workhorse/-/issues/274.

Git and Gitaly stream upload-pack response data as soon as it is
available. Some HTTP clients do not support the response being streamed
back while the server is still reading from the request body. To avoid
this, the request was buffered in to a temporary file before passing it
to Gitaly for handling. The buffer had a maximum size of 10MB, which is
now reached by requests to large repositories. These requests were then
truncated, causing Git to fail.

This commit fixes the problem by removing the request buffering and the
maximum size. Instead, the response is buffered in to a temporary file
until the request body is fully read, thus avoiding the problem of
streaming the request and the response simultaneously.

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

Support for TLS is now included.

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.

Closes gitaly#622
Closes gitaly#612

The socket path is / can be deterministic, leading to repeated
failures to open the listener when an old socket was never removed.