Entering an edited running game switches its mod set

New game / Load of the running game re-enter it in place only while it still
matches its collection; after the player edited the collection the mod set is
switched, so added mechanics (the editors) appear. Test suite collection_edit.

test_suites/collection_edit/manifest.json

@@ -0,0 +1,7 @@
+{
+  "name": "Collection Edit Test",
+  "description": "Integration test of editing the running game's collection: the novel template is entered, its collection gets the editors mechanic, back to the menu and New game of the same game must switch the mod set in-process so the editors are loaded. Activated only by --itest=collection_edit (with --game=novel_template).",
+  "sources": [
+    "src/*.cs"
+  ]
+}