Put chokidar dep into server/

Otherwise we can't carry server as a standalone folder to vendor into
the vim and ST plugins

Author: chenglou

package-lock.json

@@ -112,7 +112,6 @@
 		"typescript": "^3.9.4"
 	},
 	"dependencies": {
-		"chokidar": "^3.4.2",
 		"vscode-languageclient": "^6.1.3"
 	}
 }