[CORL-305] Speed up build process and upgrade dependencies (#2304)

* feat: speed up build process, upgrade majority of dependencies

* feat: allow specifying max cores

* chore: add some comments

scripts/watcher/LongRunningExecutor.ts

@@ -81,11 +81,13 @@ export default class LongRunningExecutor implements Executor {
         if (err) {
           reject(err);
         }
-        spawn.sync("kill", [
-          `-${signal}`,
-          this.process!.pid.toString(),
-          ...kids.map(p => p.PID.toString()),
-        ]);
+        if (kids) {
+          spawn.sync("kill", [
+            `-${signal}`,
+            this.process!.pid.toString(),
+            ...kids,
+          ]);
+        }
         resolve();
       });
     });

scripts/watcher/types/pstree.remy.d.ts

@@ -1,6 +1,6 @@
 declare module "pstree.remy" {
   export default function psTree(
     pid: number,
-    callback: (err: Error, kids: Array<{ PID: number }>) => void
+    callback: (err: Error, kids: string[]) => void
   ): void;
 }