Fix Gulp not exiting with Ctrl-C and annoying browsersync warning (#751)

## Description

(1) Fix Gupl not exiting with Ctrl-C and (2) annoying browsersync warning
- (1) make sure `gulp` is not PID 1 in container. Add `--init` option
- (2) set `open: false`

Please check the type of change your PR introduces:
- [ ] 🌻 Feature
- [x] 🐛 Bugfix
- [ ] 🗺️ Documentation
- [ ] 🤖 Test
- [ ] 🐹 Trivial/Minor

## Issue(s)

## Test Plan

<!-- How will this be tested prior to merging.-->

- [x] 💪 Manual
- [ ] ⚡ Unit test
- [ ] 💚 E2E

website/Makefile

@@ -4,15 +4,15 @@ buildimage:
 	docker build -t "corso/website:latest" .
 
 dev:
-	docker run --rm -it -p 3000:3000 \
+	docker run --rm -it --init -p 3000:3000 -p 3001:3001 \
 		-v ${PWD}:/usr/src/website corso/website gulp 
 
 shell:
-	docker run --rm -it -p 3000:3000 \
+	docker run --rm -it -p 3000:3000 -p 3001:3001 \
 		-v ${PWD}:/usr/src/website corso/website /bin/bash
 
 build:
-	docker run --rm -it \
+	docker run --rm -it --init \
 		-v ${PWD}:/usr/src/website corso/website gulp build
 
 publish: build

website/gulpfile.js

@@ -90,6 +90,7 @@ gulp.task('browsersync', function (callback) {
         server: {
             baseDir: [paths.dist.base.dir, paths.src.base.dir, paths.base.base.dir]
         },
+	open: false,
     });
     callback();
 });