Update env and optional variables

ModelSim.gitignore

@@ -1,3 +1,14 @@
+# Optional variables
+.docker
+data
+
+# Environment variables
+.env
+.env.local
+.env.development.local
+.env.test.local
+.env.production.local
+
 # ignore ModelSim generated files and directories (temp files and so on)
 [_@]*