Require config files to be explicitly created (#1040)

The behaviour of creating the config file if it's missing while
convenient causes confusion and problems when the tools are run
in the wrong folder.  They end up creating a shadow installation
and misdirect the user with nonsensical error messages, instead
pointing to the real problem which is that the tool can't find
the configuration needed to actually run.

Require a config file to be present at startup and refuse to run if this
file is missing.  To support the odd use-case of creating the config
when missing a --create-config flag is added. To conveniently generate
a config file to edit out from the "config create" command is added.

scripts/version-compat-test.js

@@ -248,6 +248,11 @@ async function main() {
 	console.log(`Testing controller ${await packageVersion("controller", options.controller)} `
 		+ `with host ${await packageVersion("host", options.host)}`);
 
+	try {
+		await run("controller", controller, ["config", "create"], controllerDir);
+	} catch {
+		// Ignore failure on previous version where config create does not exist and is not needed.
+	}
 	await run("controller", controller, ["config", "set", "controller.http_port", String(httpPort)], controllerDir);
 	await run("controller", controller, ["bootstrap", "create-admin", "test"], controllerDir);
 	await run("controller", controller, ["bootstrap", "create-ctl-config", "test"], controllerDir);