server task shouldn't assume webpack-dev-server is installed globally

[Daniel15]

All the dependencies for an app should be defined in its package.json file. However, rackt server assumes webpack-dev-server is installed globally, resulting in an error like this when running it if you don't have webpack-dev-server installed globally:

bash node_modules\rackt-cli\bin\rackt server
/c/src/react-autocomplete/node_modules/rackt-cli/bin/../tasks/server: line 3: webpack-dev-server: command not found

Instead of looking for a global webpack-dev-server, it should instead be executing ./node_modules/.bin/webpack-dev-server.

npm global packages are only supposed to be used for packages that operate globally and are not a dependency of the project itself (for example, create-react-app or yeoman). They're not the correct thing to use for something like webpack-dev-server which is a project devDependency.