Support for Merge Request Description Template in Create Merge Request dialog

[SamoylovMD]

Our team actively uses Description Template feature in GitLab EE, which is not supported by current version. Description input area is empty when we create Merge Request from Gitlab Projects plugin. Do you plan to add support for this feature? https://docs.gitlab.com/ee/user/project/description_templates.html#creating-merge-request-templates