Documentation/gitlab workflow

docs/assets/images/merge_request_workflow.png

docs/get-involved/build-environment/windows.md

docs/get-involved/contribute.md

...ed/contributor-tutorial/git-installation&configuration.md

...ibutor-tutorial/videos/Git_Installation&Configuration.mp4

...ed/contributor-tutorial/videos/Merge_Request_Workflow.mp4

...nvolved/contributor-tutorial/videos/SSH_Configuration.mp4

docs/get-involved/get-source-code.md

docs/get-involved/merge-request.md

mkdocs.yml