makebuildserver: add page (#3634)

pages/common/makebuildserver.md

@@ -0,0 +1,12 @@
+# makebuildserver
+
+> Create an F-Droid build server virtual machine.
+> More information: <https://f-droid.org/en/docs/Build_Server_Setup/>.
+
+- Create a new virtual machine or update an existing one (if available):
+
+`makebuildserver`
+
+- Force creating a fresh virtual machine:
+
+`makebuildserver --clean`