Watcher infrastructure (#1724)

* wip

* Adding chokidar and types

* specifiying build tasks

* new structure, new types, executor and watchers

* Adding log

* Fully implemented watchers

* adapt vscode launc

* Add .babelrc.js to toplevel tsconfig project

* Typo

* Get schema path from .graphqlconfig

* Use watcher binary

* Add joi validation to watcher

* Remove fb-watchman for now

* Use correct ignore path

* Fix dist folder

* Allow setting watcher

* Per default only spawn one process at a time

* Support runOnInit

* Rename RestartingExecutor to LongRunningExecutor

* Use debounce instead of throttle

* Remove console log

* Debounce command execution

* Simplify debounce

* Watcher name change

* Typos

* Rename "watcher" root level config to "backend"

scripts/watcher/bin/watcher.ts

@@ -0,0 +1,19 @@
+#!/usr/bin/env ts-node
+
+import program from "commander";
+import path from "path";
+import watch from "../";
+
+program
+  .version("0.1.0")
+  .usage("<configFile>")
+  .arguments("<configFile>")
+  .description("Run watchers defined in <configFile>")
+  .action(configFile => {
+    let config: any = require(path.resolve(configFile));
+    if (config.__esModule) {
+      config = config.default;
+    }
+    watch(config);
+  })
+  .parse(process.argv);