Implement git refs API for listing references (branches, tags and other) (#5354)

* Inital routes to git refs api

* Git refs API implementation

* Update swagger

* Fix copyright

* Make swagger happy add basic test

* Fix test

* Fix test again :)

vendor/gopkg.in/src-d/go-git.v4/worktree_linux.go

@@ -0,0 +1,26 @@
+// +build linux
+
+package git
+
+import (
+	"syscall"
+	"time"
+
+	"gopkg.in/src-d/go-git.v4/plumbing/format/index"
+)
+
+func init() {
+	fillSystemInfo = func(e *index.Entry, sys interface{}) {
+		if os, ok := sys.(*syscall.Stat_t); ok {
+			e.CreatedAt = time.Unix(int64(os.Ctim.Sec), int64(os.Ctim.Nsec))
+			e.Dev = uint32(os.Dev)
+			e.Inode = uint32(os.Ino)
+			e.GID = os.Gid
+			e.UID = os.Uid
+		}
+	}
+}
+
+func isSymlinkWindowsNonAdmin(err error) bool {
+	return false
+}