setuped route and made navbar divided launches screen into 3 parts

[amit-k-umar]

No description provided.

[AdityaPratap006]

I reviewed your PR and would like to point out some things:

1. Write the CSS of every component or screen in their separate files, instead of putting all the CSS in app.css, it will look cleaner that way.

2. You had to create a launch detail screen for a particular launch, so before listing all the launches, there's no point in making the launch detail screen :)

And from now on, make the pull request to "amit-k-kumar-PR" branch and not the "master" branch.