glab: add page (#4254)

pages/common/glab.md

@@ -0,0 +1,28 @@
+# glab
+
+> GitLab CLI tool to help working with GitLab from the command line.
+> More information: <https://clementsam.tech/glab/>.
+
+- Create a merge request:
+
+`glab mr create`
+
+- List merge requests:
+
+`glab mr list`
+
+- Create a new issue:
+
+`glab issue create`
+
+- View and filter the current repository's open issues:
+
+`glab issue list`
+
+- List pipelines:
+
+`glab pipeline list`
+
+- Clone a repository into a specific directory:
+
+`glab repo clone {{user}}/{{repository}} {{directory}}`