Additional issue tracker and portfolio mgmt/agile solutions integrations

• Expand our suite of issue tracker and portfolio mgmt/agile solutions integrations into GitLab.

Integrations

• https://gitlab.com/gitlab-org/gitlab-ee/issues/2415 Microsoft Team Foundation Server (TFS)
• https://gitlab.com/gitlab-org/gitlab-ee/issues/1187 HPQC / HP ALM
• https://gitlab.com/gitlab-org/gitlab-ee/issues/169 Rally
• https://gitlab.com/gitlab-org/gitlab-ee/issues/3306 AgileCraft
• https://gitlab.com/gitlab-org/gitlab-ee/issues/3958 G-suite